account deleted, still receiving message "authentification failed"

[H Sommer]

Hello alltogether,

I deleted an account in K-9 (Version 5.6) but still I am getting everytime K-9 calls up mails the message saying "authentification failed for account xx". I am working with Android 8.0 and before deletion K-9 worked fine.

Can anyone help me to resolve the problem?

Thanks a lot,

Hans