This started out as a post at WPMUDEV.org asking for help to fix my problem. However, I figured out the fix myself as I was putting this together so I left the post and the fix in case someone else runs into the same problem.
Background for Original Site:
–WordPress MU SubDirectory install @ primarydomain.com (WP Version 5.0.2)
–WPMU DEV Dashboard Version 4.6
–Domain Mapping Version 4.4.3.3 Network Activated with mappeddomain.com as the SubSite
–Apex XPro Version 2.4.6 installed NOT Network Activated
–Apex XPro Child Theme NOT Network Activated – ONLY Activated on mappeddomain SubSite
–I am using a single user with SuperAdmin Privileges.
Original Site
Domain Mapping Settings:
I then go to the SubSite Dashboard. When I go to the Pro => Content to display the content pages (the URL is: https://primarydomain.com/mappeddomain/pro/#/content/) and click on the page to preview it, I get the following error and XPro does not dispay the content to edit:
Preview URL: https://mappeddomain.com/
I correct this by using changing the URL to: https://mappeddomain.com/pro/#/content/ and all works well as long as https://mappeddomain.com/ remains and not the Network Domain URL.
Current Problem:
I created a complete staging site using Softaculous Staging Setup at https://primarydomain.com/sitestage/.
Now when I login to the staging site, and go to the SubSite Dashboard, the URL is:
https://primarydomain.com/sitestage/mappeddomain/wp-admin/index.php.
When I go to Pro ==> Content the following URL loads and I get a 404 error: https://mappeddomain.com/sitestage/pro/#/content.
I tried putting in https://primarydomain.com/sitestage/mappeddomain/pro/#/content,
it kicks me back to https://mappeddomain.com/sitestage/pro/#/content with a 404 error.
Fix for the problem
The Fix for the problem is to Disable Domain Mapping for the entire network.
Just do not forget to Network Activate Domain Mapping before pushing the changes back to the production site in Softaculous.