That’s a Windows error message, that we have seen with Console logins before but I don’t know that there is a single “root cause” to fix all instances. There may be some useful info in this thread at Windows 2016 Console Login Issue - “Sever Busy”
Some of the common things seem to be
- Make sure the Console machine can access any CRL urls required to validate certificates.
- Configuration of IE Hardening settings
- Checking that there are no unexpected certificates in the Personal store of the service account that runs the BESRootServer services.