The sending server could not find where to deliver: the recipient domain has no usable MX or A record.
Hard bounce · permanent
Common causes
- Domain has no MX record
- MX points to a host name that does not resolve
- Domain expired
How to fix it
- Run an MX lookup on the recipient domain
- If it is your domain, fix the MX records at your DNS host
MX CheckerRun the right check for your domain or paste the full bounce message for a precise explanation.
Open MX Checker →Frequently asked questions
Can I send to a domain without MX?
Senders fall back to the A record, but most domains without MX simply do not receive email.