Thunderbird for Android troubleshooting outbound mail

A user aided by AI has looked at this issues and summarised they're findings on the below github ticket. Note that developers have not yet responded or assesed the validity of the users summary.

https://github.com/thunderbird/thunderbird-android/issues/9558#issuecomment-5741878271

Extract

When a send fails while waiting for the server's reply to the final dot of DATA, Thunderbird cannot know whether the message was delivered. It deliberately marks the failure permanent so the message is never sent twice. That decision is reasonable. What is missing is everything after it: the user is never told the message may already have been delivered, is given no way to resolve it, and sees only "Unable to send message".

If you know the recipient hasn't received the email, you can try moving it to draft, or edit as new message and send it again.

Removing the email from the outbox will stop the silent failed to send notifications.

I don't know if the recipient actually received the email. What I want to figure it is why it's not sending the email. Is it invalid address, server config issue. I get literally nothing hat tells me why it's not being sent. That's the big compliant I have. I can login to the webmail on my provider and send it fine from there.

What I want to figure it is why it's not sending the email. Is it invalid address, server config issue.

It's neither

Assuming the respondents summary on the github ticket is accurate,

A failure occurred while trying to send the message. Temporary network loss, poor signal, server error are all possible causes. The failure happened during an important part of the communication. The app didn't receive the final signal back from the server and doesn't know if the email was successfully sent or not.

To avoid sending a duplicate email, the app flagged the email in outbox as a permanent sent failure and will never attempt to resent it again. This is by design and internal to the TB android app. It doesn't affect your web mail or stop other emails sending successfully from the app.

In order to sent this message again from the app, you need to move the email from outbox to drafts. It then looses the error flag and can be resent.

If you've already sent it again via your web mail, deleting the offending email from the apps outbox will stop the silent notification you included in your first post.