Hi,
I want to reply to this thread to reopen as I am experiencing the same problem.
I have gone through the process of applying for Google Key and entered the key on the plugin settings, however, the website still shows a “no key” error.
Here are screenshots of the settings: https://monosnap.com/file/A14dPdahQbhpatolMfyk1F34cDdKUR
And a screenshot of the website error: https://monosnap.com/file/sHDy4QVjzVtKnPOfR0MY39KMiTElSY
This website has other plugins that utilize the Google Maps API key (different keys) and they have no issues. Only the Events Calendar seems to be a problem.
Any help is appreciated.