I’m facing the same issue in 10.6.1, the manager fails to start!
What could be the issue here?
You need to make sure that the Arcgis server service is running, if not please try to start it. Otherwise, you need to go to the properties of the service change the user account to ./Arcgis and type its password. Kindly find the screenshots below:
Many thanks Majdoleen for the help.
Have you figured out why the ArcGIS Server has been installed having its Windows service turned off?