the_permalink() is not working

I have installed wordpress several times and never had this problem before.

It seems to be <?php the_permalink() ?> that’s not working.
It’s on index.php but also if I put it anywhere else, like when using WP_Query.

The default permalinks work, but when I change to custom /%postname/ it’s not working anylonger.

Check it out here: https://test.rasmart.se/
I switched to the default theme so you can see it’s not working with it either.

Try clicking on The post “Hello World” and you’ll see what happens.

Originally I had the problem on https://rasmart.se/
If you check it out, it’s at the very very bottom of the page, to the left a little link called “testar”.

The webbhost is called Loopia.se and I have several wordpress blogs using them and this has never been a problem before. They told me to reinstall wordpress which I did on https://test.rasmart.se/ and it’s still not working.

This is driving me insane.

Anyone knows how to solve this?
I’ve checked the .htaccess and it says tha same as all my other blogs.

Please help me!

Thanks
/Malin