Thank you for taking your time. Never thought for a second that I was getting brushed off. Ironically between my first post and now my other site auto-updated. I have just checked my other site after the WP upgrade and it too now is “broken” when trying to use the customizer menu.
No one else is complaining… maybe I’m the first 🙂 Since you are not able to replicate, that points me back to the host.. I agree with that so I will work further to eliminate GP. Still have a hard time with the fact that you can go right to the URL of http://www.<domain>.com/wp-admin/admin-ajax.php and get the response, but when called from a specific plugin call you get a 404. Rhetorical question, but how can that be? How can a web server decide to respond 200 for a URL typed in a browser address bar and 404 for the same URL when called from software?
I did try the ideas in the thread you quoted… no joy there as well.
Maybe it is server related, I would not discount that either…. but what exactly about the server do we feel could cause such an anomaly? My host tells me it is the software (WP or GP) because you can go to the URL directly and not get a 404. The software tells me it’s the server because it isn’t broken elsewhere. It’s an enigma wrapped up in a conundrum 🙂
I’m not giving up… will keep trying on a local install on my PC to see what happens. Thanks again.