Hi @Breuer-OAdmin ,
if all user accounts are blocked by Conditional Access you have to open a support ticket with Microsoft.
If you can't login to submit a support request the best option might be to call Microsoft's Global Support: Global Customer Service phone numbers
Source: What to do if you're locked out
(If the reply was helpful please don't forget to upvote and/or accept as answer, thank you)
Regards
Andreas Baumgarten