Route inbound mail to the right provider
Publish the MX values supplied by the mail provider in the authoritative DNS zone. Check the exact hostnames and preference values; an incorrect target can send mail to the wrong system or leave the domain without a working recipient route.
If multiple MX records are listed, preference values influence which destination is tried first, but providers may have specific redundancy guidance. Follow the service's instructions rather than inventing extra records.
Protect existing mail flow during changes
Before replacing MX records, identify the current provider and any services that rely on inbound delivery. Keep the old configuration available during a planned transition and coordinate the cutover with mailbox readiness.
After saving, query the authoritative records and send controlled tests to addresses you can inspect. DNS caches may retain the old route for a period; avoid deleting the previous mail setup until delivery to the new destination is confirmed.