Where can I find more information about this error? Nothing is appearing in logs, the error message itself has no useful data.
An AJAX HTTP error occurred.
HTTP Result Code: 500 Debugging information follows.
StatusText: Service unavailable (with message)
Some background info:
Just grasping at straws this point, and may actually completely rework how this feature will work, but just in case anyone has any bright ideas:
Product variations exist in Commerce, certain options refresh the form via Ajax (this is a built-in commerce function), and on refresh any attribute/field that is no longer available is not included with the refreshed form. Again, total standard Commerce function.
I have used a few modules to help me create variations, such as Bulk Product Creation, and as recently has 1 month ago used the exact same process to do this successfully. That product is still working.
When I inspect the ajax call itself there's nothing really unique to this vs. the other working product(s).
I have tried eliminating variations, increasing PHP memory/POST stuff, etc., and have also turned on full error reporting.