I answered @Kedmun in private because I found a vulnerability in his public development stage and than I forgot about that tread.
The reason was, that mod_version wasn’t enabled on a shared GoDaddy host.
If you have the same problem, either activate mod_version for your apache or if you can’t enable it, you can delete or comment out all the <IfVersion >= 2.4> lines in .htaccess to match your setup.