Google internal search engine stopped working

Greetings!

About 6 weeks ago I noticed the Google internal search engine stopped working, after about 10 years. Instead of a page of search results, I got a grey page with the words cse.google.com refused to connect somewhere in the middle.

I know Google stopped supporting Iframes recently, and the search engine used them. Also I have Contao 2.11.5, which is very old. Other than that I have no idea what could be the cause. There is html code in two places.

Any help or ideas gratefully received.

Kind regards, Andrew.