Recently we have begun observing some SMB errors logging on our 2k12 R2 servers indicating a failure connecting to a share. We have a NAS appliance servicing the share(s) in question via SMB3. Thus far we have bee unable to identify an issue at either the client nor the server level, so it has been very frustrating.
One thing I can say is that the issue only occurs sporadically and not on all machines, so my inclination is that it is something on the Windows side, but I'm just not certain.
Below is an example of the error.
The network connection failed.
Error: The transport connection is now disconnected.
Server name: \xxxxxxxxxxxxxx
Server address: xx.xx.xx.xx
Connection type: Wsk
This indicates a problem with the underlying network or transport, such as with TCP/IP, and not with SMB. A firewall that blocks port 445 or 5445 can also cause this issue.
Thanks in advance!