I can connect to mailbox.org and my self-hosted Nextcloud using both the integrated WebDav client and Davx5. I have actually set up my own Nextcloud using the Murena account.
However, when I want to use one of the two WebDav servers on Seedvault, whether set up via the integrated WebDav client or via Davx5, I always get the generic error message “Backup failed.”
I can’t find a useful solution for this on Gitlab or anywhere else on the internet.
do you run nextcloud in php-fpm behind an nginx? they can’t do chunked uploads. Apache can. See this entry (seedvault issue got deleted, probably disclosed some token, but this commit alludes to the issues).
Frankly I need to test seedvaults own webdav implementation, have no 1st hand experience of it yet.
If that doesn’t fit you I’d look at the access.log while you run a sync