- Plesk for Linux
Messages are stuck in mail queue and the following error message appears in
PLESK_INFO: 421-4.7.0 This message does not have authentication information or fails to pass 421-4.7.0 authentication checks.
DKIM/SPF support is disabled for the domain.
Note: If you are a domain owner, please contact your service provider for assistance with mail configuration.
Enable DKIM and SPF support: