K9 refuses to send some emails

I received an email from someone I know; i wrote an answer to the message; my answer is pending in the “sending” folder since 12h. In the mean time, I have been able to send other emails to other people. When I go in this folder and ask to send pending messages, I see a very brief system notification for a fraction of a second, then, nothing. No error message.

The only thing I have found in logcat:

10-21 23:08:41.119 20462 20477 V MessagingController: Skipping sending message K9LOCAL:5ec8b8db-0a66-4dbd-bc8b-5a9ef566dad9

I have ticked both debugging things. And thats the best I can get.

The message I am trying to send is for work, to my boss, about a client; for tonight, I have re-written the message on my computer … but, it’s not acceptable to me to have random messages blocked by my MTA without even a notification, an explanation, an error message. I did not even get a rejection notice, or a delivery pending notification in Android.

Does my boss smell bad today ?