If pgtim.bw is your valid domain, both internally and externally, then the external MX is not pointing at your ZCS server. The IP 41.216.215.117 does not resolve to any host neither
Code:
dig -x 41.216.215.117
; <<>> DiG 9.5.1-P2 <<>> -x 41.216.215.117
;; global options: printcmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NXDOMAIN, id: 5486
;; flags: qr rd ra; QUERY: 1, ANSWER: 0, AUTHORITY: 1, ADDITIONAL: 0
;; QUESTION SECTION:
;117.215.216.41.in-addr.arpa. IN PTR
;; AUTHORITY SECTION:
41.in-addr.arpa. 7031 IN SOA ns1.afrinic.net. dnsmasters.afrinic.net. 2009090412 10800 7200 1814400 7200
;; Query time: 1 msec
;; SERVER: 192.168.1.103#53(192.168.1.103)
;; WHEN: Fri Sep 11 09:05:30 2009
;; MSG SIZE rcvd: 107