Hope everyone is doing well!
I am currently trying to upgrade our enterprise deployment from 10.6,1 to 10.7.1 using the following guide Upgrade your ArcGIS Enterprise portal—Portal for ArcGIS (Windows) Installation Guide | ArcGIS Enterprise. I have upgraded the portal component without any issues and licence it without any issues. However when trying to register the new web adaptor I am getting the following error "Failed to get administrator token from Portal. Please verify that the Portal URL specified can be accessed successfully". I've been into the portal admin via the machine and port number and found a web adaptor was still registered is that normal? I have removed the adaptor in question and are still getting the same error above. Have cleared all browser caches,checked IIS etc all looks to be in order.
Any thoughts on anything i can try feeling really stuck?