After host computer reboots viewer will not connect. The connection windows show it as logged on and the thumbnail shows current image of the lock screen, but never opens just says connecting to ...hyper-v please wait. Host is Windows Server 2019 Remote Host and Viewer version 7.
Could you please let us know if you mean that your connection get stuck at the window with "digital world map" screen when connecting to the remote Host? Or do you mean that your "Full Control" window gets greyed out and Viewer tries to reconnect to a remote Host? In case if it's the latter, please double-check if Host restarts on the remote machine properly - in case if Host cannot start automatically after the machine is rebooted, it might be caused by some antivirus/firewall software activity. In this case please try referring to this KB article and see if it helps to resolve the issue.
Please let us know if the solutions above helped or if the issue persists.
Could you please try enabling the Use legacy capture mode feature in the Host Settings -> Other tab and see if this helps to resolve the issue? After enabling the feature please restart your Host in order for the changed to be applied.
In addition, please double-check if the rfusclient.exe file is present in the Host installation folder C:\Program Files (x86)\Remote Utilities - Host\* as the issue might be occurring in case if rfusclient.exe was accidentally removed (for example, by some antivirus software). In case if the file was indeed removed from the folder, then please try re-installing Host and make sure to add the Host installation folder to the antivirus exception list as described here.
Last but not least please make sure to update your RU installation to the latest version 220.127.116.11 - it's available for download on this page or via Self-Update feature. When updating please make sure to update both Host and Viewer to the same version in order to avoid the version mismatch.