This could be a clue. Problem is, that I use two factor authentication. This does not combine with this setting but requires an "App Password" to be used.
How this is working with K9 I don't know.... -- You received this message because you are subscribed to the Google Groups "K-9 Mail" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/k-9-mail/b29465d0-279e-41fe-bf1c-8e2e1be8a1b5%40googlegroups.com.
