Thank you for the suggestions. I have tried all the simple "unclicking" suggestions, and since there were not proxy settings anyway, they did nothing to improve the situation.
However I have just tried the suggestion:
'Open an administrative command prompt and type the following
netsh winhttp reset proxy
In this case the console window should have looked like this:
But instead it looked like this:
The problem still exists, even though no proxy is involved - but does the "Error ...." message give someone a clue that might help me?