From Ubi forums:
"We are aware that some of you are experiencing an issue where you are locked out of your account.
This is usually caused by having crafted a High-End backpack. We are
looking to resolve this, it’s one of our main priorities at the moment.
To help us do this, we’d like to ask people to respond to this thread answering to the following questions:
Gamertag on platform:
How long have you been locked out:
Did you craft a High-End Backpack:
Did you have issues with missing items before being locked out:
Was your inventory full or overflown (over capacity):
What was the last thing you did before logging out:
Are you getting any error codes:
Apologies for the inconvenience, and thank you for your cooperation"