I just got this as a response from my support ticket:
(FYI for the rest of us)
*****
I'm very sorry for the problems you're having with your services. It
looks like the server you're on has gotten a bit overloaded since we
stopped setting up new customers on it. Unfortunately, there's no way for
us to predict how many resources will be used when adding customers to a
machine, and it looks like the users on this server are just more
resource intensive than they are on other ones. Our admins are currently
working on reducing the load and this server is currently having 300
accounts offloaded from it to another server to help improve the
stability. Unfortunately, this won't be an immediate fix (we're expecting
the moves to finish within 24 hours), but it should improve the stability
of your server in the long run. Once this move is done, our admin team
will re-evaluate the server to determine if there's more we need to do.
Rest assured, this server is at the top of our priority list to get
running smoothly. Again, I apologize for any inconvenience this causes
you. Please let us know if you have any further questions regarding this.
Thanks!
Dan W