Nextcloud user-agent missing?
While testing my nextcloud server on pinephone/mobian (current snapshot on bookworm/sid) and gnome-online-accounts (3.40.0-2), it failed to authenticate multiple times even if credentials were right. After review, I found in my webserver log that connection attempts were done with empty user-agent which was blocked on my webserver. once rule was removed, I could connect fine.
REDACTED_IP - - [15/Sep/2021:22:27:19 +0000] "GET /nextcloud/remote.php/webdav/ HTTP/1.1" 403 135 "-" "-"
From quick repo review, maybe just a missing g_object_set
user-agent in https://gitlab.gnome.org/GNOME/gnome-online-accounts/-/blob/master/src/goabackend/goaowncloudprovider.c but I would expect this to be globally defined unless specifics like #64 or 1fdeed0d