I think I'm having a similar problem. I've been able to access the server through Finder completely fine up until a few days ago. Now, the server just appears and disappears in the Network tab in Finder. When I try to find the server using an MS laptop, the same thing happens. When i try to connect to the server, some of the error messages I'm getting are:
1. There are no shares available or you are not allowed to access them on the server.
2. This file server will not allow any more users.
3. This server may not exists. Please check the IP address.
Sometimes I get to the login credentials window, sometimes not. Even when I log in correctly, I'll get one of the random three error messages.
I've attached my diagnostics zip as well.
islademuerta-diagnostics-20231127-1850.zip