Nextcloud Internal Server Error

[christiaan]

I was installing some apps in Nextcloud out of curiosity and managed to get locked out with this message. Not sure what to do.

Internal Server Error

The server was unable to complete your request.
If this happens again, please send the technical details below to the server administrator.
More details can be found in the server log.

[doodlemania2]

Did you try restarting your container? that sometimes helps me. If not, go grab the logs and let's see some errors and we can probably crowdsource some help

[christiaan]

Thanks doodlemania, yes I tried restarting Nextcloud (and rebooting the whole server) last night without success.

I remember now, I think it was the External Storage backend for Dropbox app I had just downloaded and enabled and then tried to remove. At some point, I saw a message pop up saying this app can't be installed because it makes the server unstable.

So this might be relevant?

2020-05-08T21:58:58.000Z [Fri May 08 21:58:58.060240 2020] [php7:error] [pid 19103] [client 172.18.0.1:57688] PHP Fatal error: Interface 'OCA\Files_External\Lib\Config\IBackendProvider' not found in /app/data/apps/files_external_dropbox/lib/AppInfo/Application.php on line 31, referer: https://[mydomain]/settings/apps/files/sharingpath

[christiaan]

I disabled files_external_dropbox via terminal and restarted Nextcloud but didn't help.

[jdaviescoates]

@christiaan have you tried completely deleting the relevant folder?

[christiaan]

@jdaviescoates this one?

/app/data/apps/files_external_dropbox/

Just deleted now and restarted container without success.

[jdaviescoates]

@christiaan perhaps time to go back to your last backup and restore that?

[christiaan]

I started disabling every third party app and then reloading URL each time and this one solved my problem:

sudo -u www-data php occ app:disable files_external

I don't remember actively installing that one. Isn't that on by default? Or maybe it was a default app (you can't remove it) but it wasn't enabled and I enabled it.

Thanks for the help @jdaviescoates

[christiaan]

This post is deleted!

[christiaan]

This post is deleted!

[girish]

@christiaan I think you bring up a good point about what apps are pre-configured/pre-installed in the package is not clear up front. I will add this to our docs because it helps in debugging like in your case.

On a side note, Nextcloud apps are a constant source of frustration during updates. So, it's best to install as few as possible. I even put this note in our docs (https://cloudron.io/documentation/apps/nextcloud/#email) :

We do not recommend installing apps in Nextcloud unless absolutely 
required. Maintaining such systems is a security hassle since you
need to keep them up-to-date. Apps often break when Nextcloud is
updated and you have to know how to fix them. Finally, Apps are not
run  sandboxed. This means that a faulty plugin might compromise the
whole app and also not make the app work at all.

[girish]

I was hoping to find the list of default apps in nextcloud docs but couldn't find it. The default is below. Cloudron only install the ldap app extra.

root@329ac7c9-1419-4f18-bff2-3cbe0743d8d0:/app/code# sudo -u www-data php -f /app/code/occ app:list
Enabled:
  - accessibility: 1.4.0
  - activity: 2.11.0
  - cloud_federation_api: 1.1.0
  - comments: 1.8.0
  - dav: 1.14.0
  - federatedfilesharing: 1.8.0
  - federation: 1.8.0
  - files: 1.13.1
  - files_pdfviewer: 1.7.0
  - files_rightclick: 0.15.2
  - files_sharing: 1.10.1
  - files_trashbin: 1.8.0
  - files_versions: 1.11.0
  - files_videoplayer: 1.7.0
  - firstrunwizard: 2.7.0
  - logreader: 2.3.0
  - lookup_server_connector: 1.6.0
  - nextcloud_announcements: 1.7.0
  - notifications: 2.6.0
  - oauth2: 1.6.0
  - password_policy: 1.8.0
  - photos: 1.0.0
  - privacy: 1.2.0
  - provisioning_api: 1.8.0
  - recommendations: 0.6.0
  - serverinfo: 1.8.0
  - settings: 1.0.0
  - sharebymail: 1.8.0
  - spreed: 8.0.8
  - support: 1.1.0
  - survey_client: 1.6.0
  - systemtags: 1.8.0
  - text: 2.0.0
  - theming: 1.9.0
  - twofactor_backupcodes: 1.7.0
  - updatenotification: 1.8.0
  - user_ldap: 1.8.0
  - viewer: 1.2.0
  - workflowengine: 2.0.0
Disabled:
  - admin_audit
  - encryption
  - files_external

[girish]

To add, the answer is that all the apps under apps/ are pre-installed as per this comment in code.

So, https://github.com/nextcloud/server/tree/master/apps is the list