Google Maps for Event Manager plugin - maps not showing

Hello Elgg community!

I am using elgg 2.3.8.

It is fresh installation. The Event Manager ( plugin by @Jeroen Dalsem) works great but I am able to see the event locations only in the first event that was set up on the website. 

All next events can have added locations but the maps are not showing either during setting up the event nor on the event page.

I have a valid Google Map API with added urls and validated domain name of the website.

Any suggestions on how to fix the problem??

Many thanks in advance!