Emails with attachments send, but the Thunderbird shows them as unsent

[inktomi]

Checklist

• I have used the search function to see if someone else has already submitted the same bug report.
• I will describe the problem with as much detail as possible.

App

Thunderbird for Android

App version

13.0

Where did you get the app from?

Google Play

Android version

Android 16

Device model

Pixel 10 Pro

Steps to reproduce

Send an email with an attachment, note that it reports not sending.
Check the email you sent it to - note that it DID send.
Go back to thunderbird, see that the email is still in the outbox and that you have a notification locally of the failure.

This reproduces on my Fastmail account nearly 100% 

Expected behavior

Emails that sent should not be reporting that they didn't send. Emails with attachments should send properly.

Actual behavior

Emails with attachments report failing to send, but in fact do send.

Logs

No response