Responsive Design not working/Theme TwentyEleven

Hi, I have Theme TwentyEleven, but the responsive design does not work with one of my redirects (salalah-tour.com):

salalah-tour.com: it is a redirect and has to switch to tour-salalah.com (in responsive design), but the URL does not change and it does not show up in responsive design.

On the other hand, the redirect salalah-tour.de switches to tour-salalah.de and appears therefore in responsive design.

I don’t know what is wrong with the first redirect. I did it in the same way as the second one (salalah-tour.de) that works.

I would appreciate it very much if you could help me :-).

Thanks a lot!
Kind regards,
Konni