[SOLVED] Why is EXIM not able to verify sender?

Why is EXIM not able to verify sender?

Puzzling problem sending emails from one server to another.

Sending from Server-01 pr@example.camp TO Server-02 eman@example.edu.au

Server 02 bounces with sender verify fail for <pr@example.camp>: Unrouteable address

On Server-02 running dig MX example.camp resolves fine with:

;; ANSWER SECTION:
mus.camp.               2869    IN      MX      10 server01-aus.emanwebdesign.com.
mus.camp.               2869    IN      MX      0 server01-aus.emanwebdesign.com.

;; AUTHORITY SECTION:
mus.camp.               2869    IN      NS      ns10.domaincontrol.com.
mus.camp.               2869    IN      NS      ns09.domaincontrol.com.

Also from Server-02 I can telnet into port 25 of mus.camp and verify the existence of the email address (pr@...).

Any clues as to why Exim's sender verify is failing?

Edit exim -bvs pr@example.camp returns

pr@example.camp failed to verify: Unrouteable address

Solution

Worked out the problem was that the mus.camp domain was originally hosted on Server-02 but then moved to Server-01. Server-02 however was still trying to lookup the email address within itself instead of going to Server-01.

To solve the problem I deleted the mail and dns records from Server-02. (using VestaCP).