Emails stuck in outbox semi-permanently (on K9 6.602)

Dear all

I had problems with emails being stuck in the outbox. Correcting the server name for the relevant email account seemed to fix the problem. Months later - and having tried on K9 to send few if any emails in the time between - the problem reoccurred: emails where stuck in the outbox for weeks and yet, just now, for a reason unknown, they got sent. (This is not good. An email client needs to reliably send emails.)

Here is one log.

Here is another (this second one taken after the emails got sent)