I’m having a bit of trouble and hoping someone here might have encountered a similar issue. We recently upgraded to a new server running SIMATIC Logon version 1.6, while our HMI is still using WinCC v6.0 on Windows XP. The twist is that the server is on a different VLAN than the HMI. We can ping the server and it resolves correctly via nslookup, but when we try to log in using an account (which we know exists on the server), we get the error:

> "The access to the selected computer was refused, check the network access."

Interestingly, when we connect a PC (which is directly connected to the server) to the HMI via Ethernet, the logon works fine.

For troubleshooting, IT opened all the VLAN ports (especially those used by RPC, SMB, and NetBIOS), and we even disabled the firewalls on both the server and the HMI. We also tried modifying the lmhosts and hosts files to force DNS resolution instead of relying on NetBIOS, but no luck.

Has anyone experienced something like this or have any suggestions on what might be causing the issue?

Thanks in advance for your help!

Best regards.