SonicWall support has come across an issue where Connect Tunnel or OnDemand Tunnel users might see the following errors when accessing a DFS share:
Logon unsuccessful: The user name you typed is the same as the user name you logged in with. That user name has already been tried. A domain controller cannot be found to verify that user name.
Resource is not accessible. You might not have permission to use this network resource. Contact the administrator of this server to find out if you have access permissions. The network location cannot be reached. For information about network troubleshooting, see WIndows Help.
These errors can occur if the DNS server used by the tunnel client is not configured properly. Make sure to use the same DNS server that is used by the domain on which the DFS share resides, for the following objects:
The appliance's tunnel IP address pool
The server/domain on which the DFS share is hosted