After installation, an error message says "PRTG Webserver could not be started properly". Checked that the PRTG Core Server Service is not started but the PRTG Probe Service is started. Tried to start Core Server Service manually but failed. Windows Event Log (Application) says: "The description for Event ID 0 from source PRTGCoreService cannot be found. Either the component that raises this event is not installed on your local computer or the installation is corrupted. You can install or repair the component on the local computer. If the event originated on another computer, the display information had to be saved with the event. The following information was included with the event: Could not start webserver: Signature of C:\Program Files (x86)\PRTG Network Monitor\64 bit\PRTG Server.exe is not valid"