Unable to send an email from a Plesk server to Gmail: 421-4.7.0 This message does not have authentication information or fails to pass 421-4.7.0 authentication checks

Updated October 19, 2023 14:09

Plesk for Windows Plesk for Linux kb: technical ABT: Group A

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Emails sent to Gmail are stuck in the mail queue and the following error message appears in /var/log/maillog:

PLESK_INFO: 421-4.7.0 This message does not have authentication information or fails to pass 421-4.7.0 authentication checks

PLESK_INFO: 550-5.7.26 This message does not have authentication information or fails to.

DKIM/SPF support is disabled for the domain.

Enable DKIM and SPF support for the domain.