Hi there,
Thank you for the information. I went to your server and installed a completely new installation of the WordPress and our Pro theme and the error is still there.
This shows that the problem is 100% from the hosting that you are using, unfortunately, it seems the other hosting you are using also has the same problem. We can not identify the error, but we already tested the Pro theme in the vast majority of well-known hostings and our local installations and we do not have such a problem.
Maybe there is some blocking happening on your hosting service provider such as themod_security. You will need to ask your hosting service provider to exclude the Pro editor URLs from the od_securoty rules.
I am not sure if the problem is that but the Ajax requests of the builder seem to be rejected on your server.
Unfortunately, we can not give more support regarding this and you need to consult with your hosting service provider to unblock possible cases.
Thank you for your understanding.