Hi everyone!
Investigating more on issue Sync Error 1308413 on Portable (Windows) - Windows PC - Enpass Discussion Forum, I have found that a misconfiguration of the webserver prohibited file uploads of a certain size. The vault.enpassdb file was too large to be uploaded. which resulted in an error when connecting new clients.
However, as I hade had changed the server (physically), I did not re-setup any Enpass client, as they claimed(!) that everything was just fine.
So, Enpass would claim that it synced and that everything was in perfect order, when in reality it couldn't upload vault.enpassdb, which clearly is wrong!
I thought that everything was in order, but only recognized the error, when clients started not seeing new items from other clients.
I think this is a serious bug, as it's quite misleading to the user.
Enpass should not report sync as being OK when clearly it isn't (vault.enpassdb couldn't be uploaded).
I assume you can replicate the issue if you configure a DAV server not to accept files over a certain size. In my particular case, I used the Nextcloud docker installation. That should give the same error right out of the box.
Cheers,
Steffen