We have a SQL server that the software company RDP's into remotely through our Sonicwall to make changes. Absolutely nothing has changed configuration wise. We have always been able to get in remotely from their external IP and from any local machine on the network.
Now all of a sudden none of the internal computers nor the external connection can RDP into the Server 2016 machine. It errors before it gets to the credentials with "This computer can't connect to the remote computer".
We can ping it from any machine with no issues using the IP and the server name. RDP is enabled through the Remote Settings. It just will not let any machine connect to it and I cannot see any errors in the Event Viewer.
We even rebooted and installed any updates available. Also temporarily disabled firewall and antivirus and still same issue. Have no idea how to troubleshoot the connection.