I believe that there is sometimes a problem with the cache when i connect through a private IP-address instead of always using the public address. Since I started to always use the public address and a hairpin-nat, it always works. Maybe the cache has a problem when seeing me coming from different IP addresses. This didn't however help me with my start page problem, but I have found the solution now. I will write a new post in this thread about that. Thanks for the help.