Hello psommer559. Thank you for your report, and sorry to hear about the trouble.
Quoting psommer559,
Hello
I updated Fences on a server running Windows Server 2016 from version 6.4.6.1 to 6.5.2.7. After restarting Fences, I get the error message “Fences does not appear to be running.” After teh Message, the Management screen is comming up. But the Icons don't show.
I still got the error even after reinstalling Fences!
Regards Pascal Sommer
End of psommer559's quote
From the Fences application, please select "Enable advance logging". This can be found from the "About" tab of the application, under "Troubleshooting".
In German it should look like this:

After enabling this, reboot your PC. Please let us know once this has been done, then we can take a look to see if Fences is loading up properly.
Best regards,
Adam McGuinness
Stardock Support Specialist