Maintenance for the week of December 22:
• NA megaservers for maintenance – December 22, 4:00AM EST (9:00 UTC) - 8:00AM EST (13:00 UTC)
• EU megaservers for maintenance – December 22, 4:00AM EST (9:00 UTC) - 8:00AM EST (13:00 UTC)
Mail system broken after last maint?
I got on all three of my accounts an indicator showing I have varying number of new messages and a note saying "Your inbox is full. Delete some mail to receive more." even on an account with ZERO mail in the box:

Also, I am unable to send mail on any of the accounts, too.