limonium: Please unzip the attached file to the QMapShack main directory (creates a new `tls`subdirectory with some additional DLL files) and try your online maps again!
Thanks a lot, this has solved the issue for me.
I had already tried downloading the openssl files myself, both the ones mentioned in the German as well as English error message. Unfortunately none of the files I found resolved the issue. Looking at the ones you shared I found them to be different ones.