Email notification settings do not follow a moved Mail application #8278

Steps to reproduce

• In Settings > Email notifications, choose the Mail application as the mail server (for example mail1 on node 1).
• Move the Mail application to another node (mail1 on node 1 becomes mail6 on node 2).
• Open Settings > Email notifications again.

Expected behavior

The notification settings follow the Mail application to its new node. Applications that send mail through it keep working.

Actual behavior

The settings keep the address of the old node. Nothing listens on port 25 there anymore, so every application that sends mail through these settings fails with "Connection refused". The page now shows a manual configuration with the old address, while the Mail application is listed with its new one. The admin must choose the Mail application again by hand.

The settings store only a host and a port, not the Mail application they were chosen from, so nothing updates them after the move.

Components

• Core 3.24.1-dev.3
• Mail 1.9.1