CIFS / SMB Share drops after 1h

Hi there,
I’m getting crazy… I configured a SMB share in HA, which worked for a few weeks.
But now… I’m getting the message, that the NAS-Storage failed… So I can click reconnect on that message, and within a second, the connection is there again. Perfect - I can do backups and its working… for about an hour or so, then I get the message again.
I cannot find the place, where the logs to this issue are stored.

Does anyone know the error or at least, where I can find the logs for it?

I’m struggling with the same symptoms, no idea how to fix but it was working ok.