The problem remains with VoltStats even after the connection to OnStar is fixed. It lost a lot of outstanding data between 10/19/2017 and last night. All my fantastic records are gone. My mileage between tank load froze at 10/19 and restarted from zero even though I haven't consumed any gasoline until my FMM kicked in after 6,000 more miles and that would have put me at number 3 spot in the hall of fame. I boosted my MPG cs during the FMM, and had also traveled 450 EV miles in a single day, and it isn't posted. Data was lost.
The mileage data is available from OnStar though. I can pull them myself from the Secure.MyVolt website. VoltStats has just to pull them out from the day the connection is lost to to date, but that is time consuming.