In SOLIDWORKS PDM Administration, we can connect to the Sandbox vault, but when we try to Right-Click Sandbox > Explore we see the error 

Failed to obtain a license for SOLIDWORKS PDM Professional. License server machine is down or not responding.

But we know the server is available, because we're connected and can ping XL-CAD-WInSvr, and can open from a different machine. We also checked that the ports 433, 1434, 3030, 25734, 25735  are open.

What could cause this behavior?

The client version is SOLIDWORKS PDM 2025 (SP 5.0), build number: 33.5 (B54)

The server version is SOLIDWORKS PDM 2025 (SP 2.0), build number: 33.2 (B135)

Do client and server version have to match?
 

Thanks,
Jim