[Feature] Better (sync) failure messages

[ligix]

I have searched the existing feature requests, both open and closed, to make sure this is not a duplicate request.

• Yes

The feature

It'd be cool if immich gave more information upon failure.

An example:

Immich on android fails to sync and gives up with a generic "Sync failed. Cannot process backup".
In the logs there is no obvious stack trace.
What is the issue?

The server is ran behind a vpn and the user didn't enable the vpn. Any error hinting to the fact that the connection is the thing that failed would give the user something to investigate in order to fix the issue instead of guessing.

Platform

• Server
• Web
• Mobile

[ligix]

It's not immediately actionable because there is not a clear list of error messages that requires additional information (and I hope not to encounter enough of them to create one) but the sync message would be a good starting point.