Additional instances could not be launched

You go through planning, get a group together, make your way to the instance, and then... when you try to enter the portal, you're greeted with a very annoying message: Additional instances could not be launched, please try again later.

Trying again later does nothing, its constantly busy, you can keep trying to get in the instnce for half an hour or more without any success, its annoying. and this is what i pay £8.99 a month for?

I think its about time you got this sorted, we pay to play, not to get given annoying messages.