Google maps error messages only with Vantage version 4
I've been running the Vantage directory theme since 2015 under version 3. For over a year I'm trying to update the site to the latest 4.X version. After numerous customizations with your help and months of work the new directory would now be ready, I wanted to upload it today to the live site.
Now there is still a lingering problem: Google map error messages. We have already made several attempts to fix this problem, without success. I am getting desperate. The Google API keys are filled in in both fields (Geocoder and Map). Interestingly, the API keys work finely on the live site with Vantage version 3, the error messages only occur on the staging sites with the new Vantage version. I have attached screenshots. Interestingly, when I ignore the error messages and click further, the map und geocoding work perfectly. So, I had previously assumed that the Google API keys only work at the correct live URL and that the error message would automatically disappear once the updated directory version was uploaded at the correct live URL. But, that doesn't seem to be the case. Today I performed a test: When I migrate the old Vantage directory version 3 to a test URL as a staging site, the API keys still work! Only if I then update Vantage from version 3 to version 4 (API keys staying in place), suddenly Google error messages occur when I try searching. That is, this error message has something to do with the Vantage version. Can you help me with that?
Google maps error message.jpg