Particular samba file shares not working on particular device

I am using two old computers as file servers, both running desktop ubuntu 20.04. My windows 10 desktop is already connected to one (server A), but cannot connect to the other (server B) A windows 10 laptop I have can connect to both. A ubuntu 20.04 laptop I have can connecto to both.

When I try on my windows 10 desktop to connect to server B, it gives me error 0x80070035, and I cannot connect any further samba shares on server A either: that gives me "the network folder specified is currently mapped using a different username and password", even though I tried to sign in on the same username/password.