The SpamExperts destination is the server that receives mail after filtering. It must point to the actual mailbox service. Pointing it back to the filtering MX can create a routing loop.
IN THIS ARTICLE
01 Review or change a destination
- Obtain the receiving hostname and port from the mailbox provider. Confirm the domain and recipients already exist there.
- Record the current destinations and priorities before editing.
- Open Incoming > Destinations for the domain.
- Add or edit the authorised destination host, port and priority. Lower numeric priorities are attempted first.
- Use the connection check and appropriate recipient test, then send an external message through the filter and confirm final delivery.
02 Plan a migration
Prepare the new mailboxes before switching the destination. Arrange a short observation period and a clear rollback decision. Changing the filter's destination can affect mail even when the public MX records stay the same.
Common questions
Do equal priorities balance deliveries across servers?
The documented behaviour attempts equally prioritised destinations in random order; it is not a promise of evenly distributed load. Use a mailbox platform designed for your availability requirements.
Should I add an old server as a backup route?
Only if it is deliberately configured to accept and handle the same recipients correctly. An obsolete server can split mail or accept messages where users no longer look.
Why does the connection test pass but mail still fail?
Opening a network connection does not prove recipient acceptance, TLS policy or mailbox capacity. Inspect the SMTP response and delivery logs.
If the new route fails, preserve the error and restore the known working route when appropriate to the agreed migration plan. Do not repeatedly alternate destinations while users are sending, since this can scatter incoming mail across systems.