There is a problem with the On-Net GlobalPOP 56k dial access numbers in the Seattle area at least. They are returning Authentication Server Timeout, but the problem is not with our authentication servers, it is something on their end.
The Off-Net numbers are working, so in Seattle you can use 206-402-0023, and the MegaPOP numbers are working, so Seattle 206-299-0155 is up.
I have initiated a trouble ticket to get the others repaired.