The main reason for the problem was the transition from HTTP to HTTPS. This required a few adjustments:
The https web sites are considered to be separate web sites and need to be added to the list of sites that can use the google maps API key.
The javascript code gives warnings and sometimes errors if an https page is calling routines from http locations because these are considered insecure. There are many places where http://themis is hard coded, and this may cause problems.
One function became obsolete and had to be replaced by an equivalent function. This happens from time to time with APIs.
Some other minor fixes and improvements were completed. For example, fixed the Themis icon that is shown on the browser tab.
GMAG availability page does not show a map anymore:
https://themis.ssl.berkeley.edu/gmag/gmag_list.php
This page uses Google Maps, with a free API key from Google. One possibility is that the Google Maps API has been changed.