Since a couple of update minor updates ago (This could be coincidental) we have started experiencing our SMB share intermittently disappearing and not allowing connections (Had been working correctly for a few months prior to this) The connection to the same share is problematic over a FTP as well so it seems to be a server issue not a connection type issue. However something that could also be coincidental is the problem only seems occurs when a certain range of computers become connected, When they aren't the rest connect fine to the SMB share.
Is there a way to isolate what's causing the issue from the server?