CSS not being loadad all of a sudden

This seems to have happened before, buy I couldn’t find a solution. All of a sudden page styling isn’t applied. I haven’t updated anything nor changed any settings on the server - I host Dolibarr 16.04 with a hosting provider (Strato, if that is relevant).
I have tried several things, like wiping cache etc, but that doesn’t solve the problem. I also tried several browsers both on windows and on Linux.
Edge on Windows 11, Firefox and Chrome on Linux - all don’t work.
It does load correctly in Opera on Linux, but I can’t find the cause of that, either.
So if you have any suggestions as to what I could try I’d be really grateful.
Thanks for reading!

Problem seems to have solved itself. Mysterious, but I suppose its one of those ‘oh well’ moments…