Bitwarden logs out the client when there’s an error response on purpose.
I have observed that if i’m offline, the bitwarden app/extentions work perfectly fine and show me my existing vault items. But if the case is that I’m online, but my bitwarden server is offline for more than a few hours, then the app logouts and I cannot access anything until the server is back up I got an answer from the community that it is expected. (ref: Bitwarden App Logs Out if the server is not running)
So there should be an option to turn off this behavior.