Welcome to the LastPass Community.
We truly apologize for the problem with your account, we know how important your account for you and we is want to make the best, it seems the issue is related to your multifactor on file, please remove and re enable the MFA on file and try to replicate the issue, in case after you follow the steps you still get the same result, please create a support ticket, in that case we can do a deeper investigation about the issue.
Please let me know if you need additional help.
Greetings!
Verlaine | Customer Care
