If you have a Peerblocker or similar installed check that HTTP is allowed, also check your firewall and AV settings, if you have been viewing TWB fine and then it suddenly went off look back and see what programs you installed and if any settings have been changed, I am with Vodafone in Germany and I also live in Hamburg but have no problems, if you are using the TUHH net to view TWB check that they dont block certain webpages.