Cannot send mail to ABC/CBA. No route found

I got two different domain domino server running on 8.0.1.

Whenever I try to send an email to another server ABC/CBA, it will prompt no route found. But if I send to abc@cba.com then I will able to send thru.

How can I solve this problem?

Subject: SMTP Connection Document

Try defining an SMTP Connection Document in Domain 1’s Domino Directory to ABC/CBA with the following values:

Basics tab

Connection Type: SMTP Destination Server: ABC/CBA

Source Server: Domino1/Domain1 Destination Domain: CBA

Connect via: Direct connection SMTP MTA Relay Host: abc@cba.com (or IP Address)

…then execute the following Domino Console commands:

restart task router

restart task smtp

Subject: SMTP connection Document

After I added in the connection entry. I got another new error.

Maximum forwarding loop count exceeded. Message probably in a forwarding loop. Examine Forwarding Address of intended recipient in Domino Directory.

I already check the forwarding address and the field is empty.