For vPanel, have you tried going to /logout and the back? It sounds like maybe there's a session caught or something that that could clear out.

Reboot the ATA and it should be up. We've seen a few more reports of registrations dropping than normal lately (maybe due to growth) so we made a few changes today which hopefully should nip that before it starts growing into a bigger issue.

Basically we've adding more NAT keep-alive components, reduced the re-registration interval and will be rolling out a few more changes over the next few days.

Overall the combination of things should help virtually eliminate this ever happening.