Nextcloud Office Setup: Euro-Office or Collabora, and Why Your Documents Won't Open
Nextcloud Office is two pieces, the connector app you pick in Nextcloud and a document server you run beside it. Install the connector from its own row, start the server in Docker, connect it by an address Nextcloud can reach (not localhost), and lock it to your Nextcloud with the secret (Euro-Office) or the allow-list (Collabora).
Nextcloud Office is two pieces. The app you install in Nextcloud is only a connector. The editing happens on a separate document server that you run yourself, and both your browser and Nextcloud have to be able to reach it. Until one is connected, Word and Excel files do not open: Nextcloud just downloads them, and New in Files offers a folder and a text document, nothing else.
Everything below was checked in October 2026 on Nextcloud 35.0.1 (the official
nextcloud:35.0.1-apache Docker image on a Linux server, freshly installed),
with Collabora Online Development Edition 26.04.5.2 (collabora/code) and
the Euro-Office document server 9.3.7 (ghcr.io/euro-office/documentserver).
The test server was on a home network over plain HTTP. Yours should use HTTPS.
Which office suite should I pick, Nextcloud Office or Collabora?
Apps, Office & text opens with "Select your preferred office suite. Please note that installing requires manual server setup." The two cards say what each is better at. Nextcloud Office, powered by Euro-Office: "Best Microsoft compatibility", "Limited ODF compatibility". Collabora Office: "Best ODF compatibility", "Best support for legacy files". If your files are mostly Word and Excel, try Nextcloud Office; if they are mostly LibreOffice (ODF) files, try Collabora. Both are open source, and only one runs at a time: choosing one switches the other off.
Why does clicking Nextcloud Office do nothing?
On a fresh 35.0.1, the Nextcloud Office card already has its button filled in, but neither card says "(installed)". Clicking the filled-in button changes nothing, so nothing installs. Install it from its own row further down the same page: there are two apps there called Nextcloud Office. The plain Nextcloud Office is the Euro-Office connector; Nextcloud Office (Collabora) is the other one. Click Download and enable and confirm your password. Choosing Collabora's card works directly, because that is a real change.
How do I run the Euro-Office document server?
Euro-Office's installation guide says Nextcloud's own signed container "is not available yet, use the Euro-Office image until then" (signed .deb and .rpm packages exist for Ubuntu, Debian and Fedora). The secret must be at least 32 characters, and the same value goes into Nextcloud:
docker run -d --name euro-office --restart unless-stopped \
-p 9981:80 \
-e JWT_ENABLED=true \
-e JWT_SECRET=$(openssl rand -hex 32) \
ghcr.io/euro-office/documentserver:latestNote the secret you generated. The guide also recommends volumes for
/var/lib/euro-office/documentserver and
/var/www/euro-office/Data, so a recreated container keeps its state.
Then Administration settings, Nextcloud Office: enter the address and the secret, and Save. "Server settings have been successfully updated" with a version number means Nextcloud reached the server.
Why does it say "Failed to connect to localhost"?
Because Nextcloud runs in its own container, and to it localhost is
that container, where no document server is listening. Use an address Nextcloud can
reach: the server's own network address, a hostname, or (on a shared Docker network)
the container's name. Your browser must reach the same address too. A secret that
does not match the server's gives "Invalid token" instead.
How do I run Collabora instead?
docker run -d --name collabora --restart unless-stopped \
-p 9980:9980 \
-e aliasgroup1=https://cloud.example.com \
collabora/codealiasgroup1 is your Nextcloud's address: the Nextcloud Collabora will
work for. In Administration settings, Nextcloud Office (Collabora),
choose Use your own server, enter Collabora's address and Save. The
status box then shows both directions: the URL your browser uses to reach Collabora,
and the URL Collabora uses to call back into Nextcloud. The built-in CODE option is an
app you can install instead, but its app store entry describes it as "for local testing
and non-production use".
What does "Unauthorized WOPI host" mean?
Collabora fetches and saves your files with WOPI requests, and the Allow list for WOPI requests (Advanced settings) limits who may make them. Without it, Nextcloud warns that "users may download restricted files via WOPI requests". With it set to the wrong address, documents fail with "Document loading failed. Unauthorized WOPI host." On our server, Collabora and Nextcloud both ran in Docker on one machine, and Administration, Logging showed the requests arriving from Docker's gateway: "WOPI request denied from 172.18.0.1". Allowing that address fixed it. Read the address from your own log; yours may differ.
What about HTTPS and a reverse proxy?
On a real server, put the document server behind the same HTTPS reverse proxy as
Nextcloud, on its own hostname, and use that https address in both places. For
Collabora behind a proxy that terminates TLS, Collabora's documentation uses
extra_params=--o:ssl.enable=false --o:ssl.termination=true. We did not
test a proxy setup for this page.
What about Nextcloud All-in-One?
All-in-One runs the office suite for you. On an AIO install, Nextcloud's picker says office suite switching is managed through the All-in-One interface instead.
Full video transcript
1
00:00:00,000 --> 00:00:04,803
Nextcloud Office is two pieces. The app
you install in Nextcloud only connects.
2
00:00:04,843 --> 00:00:09,340
The editing happens on a separate
document server, which you run yourself,
3
00:00:09,380 --> 00:00:12,589
and both your browser and
Nextcloud have to reach it.
4
00:00:12,629 --> 00:00:15,716
Until one is connected,
your Word files won't open.
5
00:00:15,756 --> 00:00:19,149
Nextcloud thirty five gives
you two suites to pick from,
6
00:00:19,189 --> 00:00:22,337
and the page makes one look
installed when it isn't.
7
00:00:22,377 --> 00:00:23,419
I'll set up both.
8
00:00:23,819 --> 00:00:27,205
This is Nextcloud thirty
five, freshly installed.
9
00:00:27,245 --> 00:00:30,701
It runs in Docker, on a
Linux server I run myself.
10
00:00:30,741 --> 00:00:33,568
It's on my home network, over plain HTTP.
11
00:00:33,608 --> 00:00:38,502
A real server should use HTTPS, and
the page linked below covers that.
12
00:00:39,756 --> 00:00:43,717
Open the New menu. You can make
a folder, or a text document.
13
00:00:43,757 --> 00:00:47,103
There's nothing here for
Word, Excel or PowerPoint.
14
00:00:48,337 --> 00:00:53,317
Out of the box, Nextcloud stores
office files, but it can't open them.
15
00:00:53,357 --> 00:00:56,297
Click a Word file, and it just downloads.
16
00:00:58,743 --> 00:01:02,140
To change that, go to
Apps, then Office and text.
17
00:01:04,165 --> 00:01:09,381
At the top, Nextcloud thirty five asks you
to pick an office suite. There are two.
18
00:01:10,605 --> 00:01:12,361
And right under the heading.
19
00:01:12,401 --> 00:01:16,017
Please note that installing
requires manual server setup.
20
00:01:16,057 --> 00:01:19,135
That one line is what this
whole video is about.
21
00:01:20,375 --> 00:01:23,758
The first is Nextcloud Office,
powered by Euro-Office.
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00:01:23,798 --> 00:01:28,258
Its button is already filled in, so
it looks chosen. But read the name.
23
00:01:28,298 --> 00:01:31,531
It doesn't say installed.
Nothing is installed yet.
24
00:01:32,787 --> 00:01:38,035
The card says what it's good at.
Best Microsoft compatibility.
25
00:01:38,075 --> 00:01:43,704
Limited ODF compatibility. ODF is
the format LibreOffice saves in.
26
00:01:44,966 --> 00:01:47,239
The second is Collabora Office.
27
00:01:47,279 --> 00:01:52,725
It claims the best ODF compatibility,
and the best support for old files.
28
00:01:53,964 --> 00:01:56,102
So here's a simple way to choose.
29
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If your files are mostly Word
and Excel, try Nextcloud Office.
30
00:02:00,235 --> 00:02:04,420
If they're mostly from LibreOffice,
Collabora is the one to try.
31
00:02:04,460 --> 00:02:07,760
Both are open source. And
only one runs at a time.
32
00:02:09,024 --> 00:02:10,932
Here's what either one involves.
33
00:02:10,972 --> 00:02:14,159
In Nextcloud, you install
a small app, the connector.
34
00:02:14,199 --> 00:02:19,151
The editor itself runs on a document server,
a separate program next to Nextcloud.
35
00:02:19,191 --> 00:02:22,500
Your browser loads the editor
from the document server.
36
00:02:22,540 --> 00:02:27,127
And the document server fetches your
file from Nextcloud, and saves it back.
37
00:02:27,167 --> 00:02:30,333
So your browser and Nextcloud
both have to reach it.
38
00:02:31,638 --> 00:02:34,681
Start with Nextcloud
Office. Click its button.
39
00:02:38,777 --> 00:02:39,853
Nothing happens.
40
00:02:39,893 --> 00:02:45,431
It's already selected, so on this release,
clicking it doesn't install anything.
41
00:02:45,471 --> 00:02:47,981
Install it from its own row instead.
42
00:02:49,228 --> 00:02:53,563
Further down the list, there are
two apps called Nextcloud Office.
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00:02:53,603 --> 00:02:56,148
The plain one is the Euro-Office suite.
44
00:02:56,188 --> 00:02:59,767
The one with Collabora in
brackets is the other suite.
45
00:03:01,011 --> 00:03:06,958
Download and enable, on the plain one.
Nextcloud asks for your password first.
46
00:03:08,179 --> 00:03:13,268
Type it, and confirm. Nextcloud
downloads the app and switches it on.
47
00:03:21,723 --> 00:03:25,867
Back at the top, the card now says
installed. That's the connector.
48
00:03:25,907 --> 00:03:28,092
On its own, it can't edit anything.
49
00:03:29,324 --> 00:03:35,117
Now the document server. Euro-Office's
installation guide says which one to run.
50
00:03:36,327 --> 00:03:39,692
Nextcloud's own signed
container isn't out yet.
51
00:03:39,732 --> 00:03:45,455
The container image is not available yet.
Use the Euro-Office image until then.
52
00:03:46,700 --> 00:03:49,293
On the server, that's one docker command.
53
00:03:49,333 --> 00:03:52,825
It needs a secret, at least
thirty two characters long,
54
00:03:52,865 --> 00:03:55,843
and you'll type the same
secret into Nextcloud.
55
00:03:55,883 --> 00:03:59,287
I've already started it, on
port nine nine eight one.
56
00:04:00,554 --> 00:04:05,190
In Nextcloud, open Administration
settings, then Nextcloud Office.
57
00:04:06,633 --> 00:04:10,623
It wants the address of the server
with the document services installed.
58
00:04:11,845 --> 00:04:14,464
Here's the mistake most people make first.
59
00:04:14,504 --> 00:04:19,569
The server is on this same machine, so
type localhost, port nine nine eight one.
60
00:04:20,797 --> 00:04:22,221
Then the secret.
61
00:04:25,164 --> 00:04:26,511
Save.
62
00:04:27,100 --> 00:04:29,178
Failed to connect to localhost.
63
00:04:29,218 --> 00:04:34,302
To Nextcloud, localhost means its own
container, not the server it runs on.
64
00:04:34,342 --> 00:04:37,962
And there's no document
server inside that container.
65
00:04:39,225 --> 00:04:41,888
Use an address Nextcloud
can actually reach.
66
00:04:41,928 --> 00:04:45,083
Here, that's the server's
own address on my network.
67
00:04:45,123 --> 00:04:48,072
Your browser has to reach
the same address, too.
68
00:04:49,312 --> 00:04:50,339
Save again.
69
00:04:53,344 --> 00:04:55,971
Server settings have been
successfully updated.
70
00:04:56,011 --> 00:04:59,830
The version number at the end comes
from the document server itself,
71
00:04:59,870 --> 00:05:01,589
so Nextcloud really reached it.
72
00:05:01,629 --> 00:05:05,319
If the secret didn't match, you'd
see Invalid token here instead.
73
00:05:06,579 --> 00:05:07,446
Back to Files.
74
00:05:07,486 --> 00:05:10,946
With the connector installed
and its server connected,
75
00:05:10,986 --> 00:05:14,163
Nextcloud now knows what
to do with office files.
76
00:05:15,375 --> 00:05:20,174
The New menu now has a document,
a spreadsheet, and a presentation.
77
00:05:22,599 --> 00:05:25,687
And the Word file that came
with Nextcloud. Open it.
78
00:05:25,727 --> 00:05:28,575
Nextcloud hands the file
to the document server,
79
00:05:28,615 --> 00:05:31,262
and the editor loads
right here in the page.
80
00:05:34,522 --> 00:05:39,896
It opens in the editor, right inside
Nextcloud. That's Nextcloud Office working.
81
00:05:39,936 --> 00:05:43,821
The connector in Nextcloud,
the document server beside it,
82
00:05:43,861 --> 00:05:46,501
and one address both of them can reach.
83
00:05:47,757 --> 00:05:49,075
Now the other suite.
84
00:05:49,115 --> 00:05:52,538
If you'd rather have
Collabora, it's the same idea,
85
00:05:52,578 --> 00:05:54,887
with two differences worth seeing.
86
00:05:56,099 --> 00:06:01,402
Click its button. This time it's a real
change, so Nextcloud asks for your password.
87
00:06:02,621 --> 00:06:07,486
It installs Collabora's connector,
and switches Nextcloud Office off.
88
00:06:07,526 --> 00:06:09,659
Only one suite runs at a time.
89
00:06:20,863 --> 00:06:24,435
Collabora's settings page
says plainly what's missing.
90
00:06:27,289 --> 00:06:31,647
Please configure a Collabora Online
server to start editing documents.
91
00:06:32,867 --> 00:06:37,846
One option is a built-in server,
installed as another app. It's convenient.
92
00:06:37,886 --> 00:06:43,266
But its own entry in the app store says
it's for local testing and non-production
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00:06:43,306 --> 00:06:43,534
use.
94
00:06:43,574 --> 00:06:45,849
For your real files, run your own.
95
00:06:47,103 --> 00:06:50,080
Collabora's server is
another docker command.
96
00:06:50,120 --> 00:06:54,639
You tell it which Nextcloud may use
it, by that Nextcloud's address.
97
00:06:54,679 --> 00:06:57,697
I've started it on port
nine nine eight zero.
98
00:06:58,951 --> 00:07:01,440
Choose, Use your own server.
99
00:07:02,649 --> 00:07:07,339
Its address, the same way. The
server's own address, never localhost.
100
00:07:08,554 --> 00:07:09,388
Save.
101
00:07:11,350 --> 00:07:15,459
Collabora Online server is reachable.
And it shows both directions.
102
00:07:15,499 --> 00:07:18,494
The address your browser
uses to reach Collabora.
103
00:07:18,534 --> 00:07:22,148
And the address Collabora uses
to call back into Nextcloud.
104
00:07:22,188 --> 00:07:24,975
If either one is wrong,
documents won't load.
105
00:07:26,235 --> 00:07:28,154
But there's a warning under it.
106
00:07:28,194 --> 00:07:31,797
You have not configured the
allow-list for WOPI requests.
107
00:07:33,024 --> 00:07:37,063
Those are the requests Collabora
makes to fetch and save your files.
108
00:07:37,103 --> 00:07:40,902
Without a list, Nextcloud answers
any server that asks that way,
109
00:07:40,942 --> 00:07:44,741
and the warning says people could
download files they shouldn't.
110
00:07:44,781 --> 00:07:47,180
The fix is to name your document server.
111
00:07:48,453 --> 00:07:52,132
So type the document
server's address, and save.
112
00:07:54,688 --> 00:07:56,773
Now open the Word file again.
113
00:07:56,813 --> 00:08:02,268
Nextcloud hands it to Collabora, and
Collabora asks Nextcloud for the file.
114
00:08:02,308 --> 00:08:05,898
That request is exactly
what the list now checks.
115
00:08:10,645 --> 00:08:14,460
Document loading failed.
Unauthorized WOPI host.
116
00:08:14,500 --> 00:08:18,918
The list is working, and it
just turned Collabora away.
117
00:08:20,160 --> 00:08:24,650
Nextcloud's log says why.
Administration, Logging.
118
00:08:25,857 --> 00:08:29,669
WOPI request denied. And
look where it came from.
119
00:08:29,709 --> 00:08:34,819
An address starting one seven two,
eighteen. Not the one I typed.
120
00:08:36,056 --> 00:08:37,721
That's Docker's own network.
121
00:08:37,761 --> 00:08:39,974
Collabora calls the server's address,
122
00:08:40,014 --> 00:08:43,079
but because both run in
Docker on the same machine,
123
00:08:43,119 --> 00:08:45,636
the request arrives from Docker's gateway.
124
00:08:45,676 --> 00:08:48,132
That's the address the list has to allow.
125
00:08:48,172 --> 00:08:51,704
Read it from your own log,
because yours may be different.
126
00:08:57,578 --> 00:09:00,024
Add it to the list, and save.
127
00:09:11,366 --> 00:09:13,184
And open the file once more.
128
00:09:13,224 --> 00:09:16,767
This time, when Collabora
asks Nextcloud for the file,
129
00:09:16,807 --> 00:09:19,859
the request comes from
an address on the list.
130
00:09:21,082 --> 00:09:23,280
It opens, in Collabora this time.
131
00:09:23,320 --> 00:09:27,321
And now only your own document
server can fetch your files.
132
00:09:29,154 --> 00:09:31,744
So, Nextcloud Office. Pick one suite.
133
00:09:31,784 --> 00:09:37,076
Nextcloud Office for Word and Excel
files, Collabora for LibreOffice files.
134
00:09:37,116 --> 00:09:39,422
Install its app from its own row.
135
00:09:39,462 --> 00:09:43,190
Run its document server in
Docker, next to Nextcloud.
136
00:09:43,230 --> 00:09:47,740
Connect it with an address Nextcloud
can reach, never localhost.
137
00:09:47,780 --> 00:09:49,731
Then lock it to your server.
138
00:09:49,771 --> 00:09:53,783
The secret for Euro-Office,
the allow list for Collabora.
139
00:09:53,823 --> 00:09:56,809
The commands are on the page linked below.