Instance Error

I can't connect to other people insances.
After i join a party i try to join their hideout and i get instance error.
"Disconected. Failed to connect to instance"
This is very annoying. I can run with other players only if i am the one that creates the instance. This error is very frustrating.
This is not for all players. looks like is only in London Server. the MS is very low in this server. Please try to fix. I can't join any party.