Erroneous outbox message fails repeatedly

[ChristophWurst]

Steps to reproduce

1. Compose and send a message
2. Run into SMTP error "Server does not support sending internationalized header data" #8165, or likely other sending errors
3. Look at the outbox

Expected behavior

The message is attempted to be sent once, then shows as failed

\OCA\Mail\Service\OutboxService::sendMessage should mark the message as failed

Actual behavior

The message is attempted to be sent with each cron job, e.g. every 5mins.

+------------+--------------+------------+--------+
| account_id | user_id      | send_at    | failed |
+------------+--------------+------------+--------+
|        123 | christoph    | 1677236522 |      0 |
|        123 | christoph    | 1677237015 |      0 |
|        123 | christoph    | 1677237164 |      0 |
|        123 | christoph    | 1677237299 |      0 |
|        123 | christoph    | 1677237430 |      0 |
|        123 | christoph    | 1677237455 |      0 |
|        123 | christoph    | 1677612832 |      0 |
+------------+--------------+------------+--------+

Mail app version

3.0

Mailserver or service

No response

Operating system

No response

PHP engine version

None

Web server

None

Database

None

Additional info

No response