Running MainWP on a subdomain shouldn’t effect it’s functionality.
You must verify before making the keys. GA has changed the work flow slightly. I believe it’s around step 14.
Contacted BlueHost support and found out that their firewall had a couple of entries blocking the connection from Google which is now being allowed to pass. Finally got a Connected status.
The problem now is that the extension is not showing the analytics data from Google. Using the Google Analytics API which shows 3 requests and 0% errors on the Google side. Google also offers the Google Analytics Reporting API and Google Analytics Data API. Why is no data being sent from Google to MainWP Google Analytics Extension? Am I using the wrong API?
Found the problem. Had to go into into Sites > Manage Sites, then in the right-most column select the ellipses button then select Edit Site. Under Google Analytics account property, select the website property URL in the drop-down.