email blocking issue

Hi AT & T,

Good day!

Our customer domain teac.com.hk can't send mail to sbcglobal.net almost two months. We sent many times to sbcglobal.net for checking, and we got the reply that there do not have any blocking of our SMTP server IPs(210.87.xxx.xx)

However, it still get an error when our customer tried to send to sbcglobal.net. It seems our customer domain teac.com.hk is in your blacklist. Could you please help to release it?

Can @ATTBusinessForums or @ATTBusinessCare assist with finding out the current status or escalate the issue for us?

Thank you so much!!

Regards

ONON

Error Message:

Reporting-MTA: dns; imsantv103.netvigator.com
Received-From-MTA: DNS; ybironout2e.netvigator.com
Arrival-Date: Wed, 21 Feb 2024 15:46:44 +0800

Final-Recipient: RFC822; [email scrubbed]
Action: failed
Status: 5.3.0
Diagnostic-Code: SMTP; 553 5.3.0 flph828 DNSBL:RBL 521< 210.87.247.8 >_is_blocked.For assistance forward this error to abuse_rbl@abuse-att.net
Last-Attempt-Date: Wed, 21 Feb 2024 15:46:45 +0800