Unable to connect to Realms

I was finally able to login with my account, but when i tried to enter the realm i was invited to, an connection error message pops up. The connection was fine. This morning worked perfectly and i played in the Realm. Only 1 hour later it started to have problems. Everything else Web-related (marketplace, server list,...) works fine. Only entering the Realm cause this error. Every other app works fine, there is connection. Only the Realms itself is an issue