Open Console shows no video on one Virtual Server

[insearchof]

VMware ESXI 6.5

Windows 2016 Data Center.

When I right click on the VM and select Open Console the video display is blank.

VMtools is installed and current

I use VNC Viewer and Team Viewer to access this server and both connect to the server but display no video

What is wrong here?

[VipalGujrathi]

Is it happening for all VMs?

Port 903 is required to open VM console. Please check if its open

[insearchof]

This is only on one (1) server.

I can run remote powershell commands on it and it is running I use Nagios to monitor the servers and no alerts from Nagios.

I just can see the console.

I checked port 903 and it is not open on this server and also checked a few others none have port 903 open.

I just restarted the server and it now has video.

Any other ideas?