When using the mail feature of Marketing Suite Deluxe you may be presented with an NDR with the following information:
Diagnostic-Code: smtp; 550 5.7.1 <email@example.com>Relaying denied: You must check for new mail before sending mail.
This situation can occur when you set up mail on this subscription but have not yet configured the corresponding MX records for the mail hosting subscription withing the first few weeks.
The hosting partner will check for the existence of the MX records for the first couple of weeks after setting up the hosting subscription with mail functionality.
If the records are found for the domain, the domain will be added to the 'Sendmail' list and will be possible to receive mail.
If the records aren’t found within the first couple of weeks, the hosting partner stops scanning for MX records for the domain and as a result is unable to receive mail.
Preferably, configure the MX records within the first 2 weeks after configuring the subscription.
If this is not possible and you receive the NDR mentioned, please create a support ticket at https://support.copaco.cloud and provide the requested information.