I am getting below error through SMTP relay server, while sending email from Qradar as Rule response. any idea what could be cause of issue.

Apr 28 15:33:31 www postfix/smtp[31244]: 39F5F19C: to=<gyan.mishraSupport Member>, relay=none, delay=0.03, delays=0/0/0.03/0, dsn=4.3.5, status=deferred (Host or domain name not found. Name service error for name=smtp.poc.com type=AAAA: Host not found)

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