Server reported no ETag using Nextcloud Client (Windows or Mac)

Hello,

I have an issue with external storage mounted over SMB, the host ist Microfocus Open Enterprise Server 2018 SP3 with CIFS enabled, over said CIFS interface we are accessing underlying NSS Volumes and everything is working just fine when you access the shares using web interface of Nextcloud, problems start when we use Nextcloud client and try to sync shared volumes.

At some point Nextcloud client stops syncing and says “Server reported no ETag” at the same time I can find following error in Nextcloud log:

App: webdav
Message: Sabre\DAV\Exception\ServiceUnavailable: Storage with mount id 7 is not available

It says that storage is not accessible, but using Web Interface of Nextcloud I can browse whole share, see all files, open and edit them, so the issue seems to be only on webdav part of nextcloud which is used for the client. By the way, the log is kind of flooded with said error, as we have multiple shares its not always number 7, but it is the same error regarding same SMB host server.

Here is expanded log message:

  1. /var/www/nextcloud/3rdparty/sabre/dav/lib/DAV/Tree.php - line 78:OCA\DAV\Connector\Sabre\Directory->getChild()
  2. /var/www/nextcloud/3rdparty/sabre/dav/lib/DAV/Tree.php - line 73:Sabre\DAV\Tree->getNodeForPath()
  3. /var/www/nextcloud/3rdparty/sabre/dav/lib/DAV/Tree.php - line 73:Sabre\DAV\Tree->getNodeForPath()
  4. /var/www/nextcloud/3rdparty/sabre/dav/lib/DAV/Tree.php - line 73:Sabre\DAV\Tree->getNodeForPath()
  5. /var/www/nextcloud/apps/dav/lib/DAV/ViewOnlyPlugin.php - line 74:Sabre\DAV\Tree->getNodeForPath()
  6. /var/www/nextcloud/3rdparty/sabre/event/lib/WildcardEmitterTrait.php - line 89:OCA\DAV\DAV\ViewOnlyPlugin->checkViewOnly()
  7. /var/www/nextcloud/3rdparty/sabre/dav/lib/DAV/Server.php - line 472:Sabre\DAV\Server->emit()
  8. /var/www/nextcloud/3rdparty/sabre/dav/lib/DAV/Server.php - line 253:Sabre\DAV\Server->invokeMethod()
  9. /var/www/nextcloud/3rdparty/sabre/dav/lib/DAV/Server.php - line 321:Sabre\DAV\Server->start()
  10. /var/www/nextcloud/apps/dav/lib/Server.php - line 358:Sabre\DAV\Server->exec()
  11. /var/www/nextcloud/apps/dav/appinfo/v2/remote.php - line 35:OCA\DAV\Server->exec()
  12. /var/www/nextcloud/remote.php - line 166:require_once(“/var/www/ne … p”)

I hoped that it is some kind of cosmetic error message, but no, after client throws this error, it stops syncing and if you browse to the shares using explorer, you dont see all the subfolders of the share, only a part of it, but at the same time if you browse to this folders using web interface of nextcloud - everything ist there and can be accessed and modified without any issues. So Im kind of clueless right now, it is working fine on the web, but has massive issues on the client.

Nextcloud version: 24.0.5
Operating system and version: Debian 11.3
nginx version: 1.22.0
PHP version: 8.1.9
Nextcloud Client: Newest version, tested on Windows an Mac

Best Regards,
Aleks