Hello Verlaine,
I found a related problem and disabling MFA solved the problem. Topic is here: Authenticator deleted account
Hello! @LastPass User
Welcome to the LastPass Community.
We really apologize for the inconvenience, we know how important it is to you and we want to help you out to get access to your account ASAP.
If you are not able to see your account in the LastPass MFA app, unfortunately we cannot reconnect or restore the account in the app, I will suggest accessing your account by using the backup method SMS or Call Me.
Please let me know if that does not work so we can work in another way.
Please let me know if you need additional help.
Greetings!
Verlaine | Customer Care
Here it shows also to fix
https://support.lastpass.com/s/document-item?bundleId=lastpass&topicId=LastPass/LastPass_Authenticator_disable_lpa.html&_LANG=enus