Undelivered Mail Returned to Sender

Undelivered Mail Returned to Sender

We got this error messasge when trying to send email.

julie.medina@, ERROR CODE :550 - 5.7.1 Service unavailable, Client host [136.143.188.14] blocked using Customer Block list AS(1420) [SG2APC01FT0007.eop-APC01.prod.protection.outlook.com]



Reporting-MTA: dns; mx.zohomail.com
Arrival-Date: Tue, 05 Jul 2022 12:17:37 +0800

Original-Recipient: rfc822; julie.medina@
Final-Recipient: rfc822; julie.medina@
Status: 550
Action: failed
Last-Attempt-Date: 5 Jul 2022 04:17:43 GMT
Diagnostic-Code: 5.7.1 Service unavailable, Client host [136.143.188.14] blocked using Customer Block list AS(1420) [SG2APC01FT0007.eop-APC01.prod.protection.outlook.com]

removed the supposed recipient's domain from this message. how can we solve this and successfully send emails?