The same thing happend to me once after a viewer change. It didn't happen to my alt. Only me, so I knew it had nothing to do with my connections or anything like that. It was litterally seconds after a viewer update. I filed a ticket but was told that that type of support was not given to non preimium members and to seek help in Wiki. Wiki could not help because it was happening to so few of us that no information was there.
The only alternative I had was to dump my AV or to just use my alt. I had far to much invested... land ownership, a business a huge and costly inventory to jusst dump my AV so I used my alt and checked in on my AV everytime there was a viewer update. This lasted two months... then one morning a new update cleared the problem and here I am today.
It seemed to have been a bug.
I feel for your frustration