I’ve had trouble before with the autoptimize plugin, which can cause JS errors. Could you try disabling it and see if the maps load?
Try the following:
1. Update MapPress to the latest version, and check the map (the newest versions whitelist MapPress in autoptimize)
2. If #1 doesn’t help, disable ALL plugins (except MapPress) and switch to the standard Twenty Twenty theme – just for a moment – and check the map again. If it works, you can reactivate one by one to find the problem.
If the map still doesn’t work, please send me a login. You can use the contact form to email me directly.