Hi folks, we've been seeing some reports about this specific issue and Sr. Server Programmer Jennifer Harkness wanted to elaborate a bit on what's been going on:
As many of you have noticed, we have been playing with the population settings for the raid areas, and in particular for Explosive Conflict. The main change is that we've lowered the overall population for those zones. We've been really happy with the reports of lowered lag that folks have been posting, so it looks like that side of the change has been a great success.
However, we have run into one unexpected effect. Normally when you zone to a new area, we try to put you in the same instance as your guild mates and friends. Unfortunately, it's doing the same thing when you zone into raid instances, which means that with the lowered population numbers, you can be the last one who fits in the instance, and there won't be room for the rest of your Operations group. This is why a few people have been getting the dreaded "Server Admin" error and end up unable to zone into Denova.
When this happens to you in a group that has just started, the best thing to do is to have everyone exit the area, then reset the group's active phases. Then you can have someone who is either unguilded or who knows their guild members aren't in a raid instance zone in first so that they get a emptier instance.
If this happens to your group when you have made progress and would have to kill your way back in, you can wait a few minutes and hope that the population drops, or you can reset your phase immediately and you should be able to enter a new instance immediately.
We did make a configuration change yesterday afternoon to help with the problem and we're monitoring the servers very closely to evaluate whether that lowers the error rate enough. We're also working as quickly as possible to get a regular fix ready to deploy.
I don't know about the rest of you but the words wait and hope should absolutely NEVER be uttered by any member of the DEVs or community managers ever again..
No wonder they can't get anything right