e-mails won't send. They just remain in outbox. Thunderbird for Android. smtp: smtp.mail.yahoo.co.uk, Security: SSL/TLS, Port: 465, Authentication: OAuth 2.0,, Username: [redacted] @yahoo.co.uk, Certificate: none.

This is the Thunderbird for desktop operating systems forum. You would be better off asking your question in the Thunderbird for Android forum where the experts reside:

https://support.mozilla.org/en-US/products/thunderbird-android

Moving this topic to the TBfA queue.

Hi Trevor.

Move the email from outbox to draft. From there you can try and send them again.

Emails that remain in the outbox after a period of time have likely been marked as permanent send failures. Once marked, the app will never try and send them again.

TBA marks emails permanent send failures under the following circumstances.

1. A temporary send failure was experiences. Poor network signal and server side issues being two examples. The app retries sending the email 5 more times, then marks it a permanent send failure.

2. The size of your email was greater than the maximum size your mail provider allows. TBA checks this size before attempting to send. If it's too big, it's marked as a permanent send failure.

The app provides a silent notification in the notification shade when emails are marked as such.

See below for more info. https://github.com/thunderbird/thunderbird-android/issues/4602