Yeah, I get this during prime times on Shattered Hand US pretty regularly. One time it probably took a good 20 minutes, but usually I just keep my guys running back and forth into the instance portal and it doesn't take more than a minute or two. It's pretty random though because you're fighting against anyone else who is trying to run into an instance and getting the message. It'd be nice if it would work queue-style as long as you stay near the instance portal or something, but it's not generally an issue
Connect With Us