An email is not deleted until the deletion is performed twice. The first time, the email is only flagged. Why is the e-mail not deleted immediately, does a setting have to be made?
Hi,
What do you mean with “flagged only”?
Which version of K9?
Imap/Pop3?
I only have IMAP so cannot tell about POP3
Did you check that trash folder is set correctly? Check at Settings / account / folders.
Also check settings on Settings / account / Fetching mail. There you have at least 4 options on deletion:
Thanks for the quick response. I use K9 version 6.200 and use POP3. Until some time ago, I was able to delete the emails in the K9 app with just one action. Now two actions are needed. Marking and deleting does not cause the email to be deleted. This only happens the second time (mark and delete again).
I live in Germany and speak very little English. That’s why I rely on the Google Translator here. Maybe he doesn’t always find the right terms. As “flagged only” he meant “marked”.
Problem solved!
The note about the settings for the mailboxes “Mark as read when deleted” has led to success. After removing the check mark there, the e-mails will be deleted immediately.
Thanks again for the quick and correct hint 
There is another reason why the emails were not deleted immediately: by mistake, one of the email accounts was set up as an imap account and all the others as a pop3 account. When all accounts were just pop3 accounts, the emails were immediately deleted.