wix finally solved this problem for me. Here is their response:
While we were trying to arrange the call, our developers actively continued the investigation process. Eventually, they were able to recreate the issue on their end once, and identify the root cause of it.
They have immediately implemented the fix, and the functionality should work now. Please, let us know if you are still experiencing an issue on your end, since the errors seem to have been connected to the specific IP addresses.