There is a Azure Virtual machine that has been running for many months. Lately attempting to RDP to the VM is causing RDP to show "an internal error has occurred" within a second of clicking connect. Attempted to setup Azure Bastion as a workaround but that was unable to connect.
Other VM's on the network can be connected to fine. Also tried rebooting the VM from the portal and then connecting to it again.
Running the RDPSettings for the VM in question reset a few keys and solved the issue.