thank you very much for your kind help.
I have root access to my VPS.
Here is the output. Kindly help.
Code:
exigrep username1@mydomain.org /var/log/exim_mainlog
root@vps [~]# exigrep username1@mydomain.org /var/log/exim_mainlog
2010-10-11 05:10:38 1P58mc-00040W-0T <= noreply@mydomain.org U=mydomain P=local S=20497 id=4cb2802de653b@mydomain.org
2010-10-11 05:10:38 1P58mc-00040W-0T lowest numbered MX record points to local host: mydomain.org
2010-10-11 05:10:38 1P58mc-00040W-0T == username1@mydomain.org R=lookuphost defer (-1): lowest numbered MX record points to local host
2010-10-11 05:10:38 1P58mc-00040W-0T ** username1@mydomain.org: retry timeout exceeded
2010-10-11 05:10:39 1P58mc-00040W-0T Completed
2010-10-11 10:50:59 lowest numbered MX record points to local host: mydomain.org (while verifying <username1@mydomain.org> from host mail-qw0-f47.google.com [209.85.216.47])
2010-10-11 10:50:59 H=mail-qw0-f47.google.com [209.85.216.47] F=<usernname2@gmail.com> temporarily rejected RCPT <username1@mydomain.org>: lowest numbered MX record points to local host
2010-10-11 10:51:20 lowest numbered MX record points to local host: mydomain.org (while verifying <username1@mydomain.org> from host outmail008.snc1.tfbnw.net (mx-out.facebook.com) [69.63.178.167])
2010-10-11 10:51:20 H=outmail008.snc1.tfbnw.net (mx-out.facebook.com) [69.63.178.167] F=<confirm+AY2FwdGFpbkBzYWZlZW5hLm9yZw@facebookmail.com> temporarily rejected RCPT <username1@mydomain.org>: lowest numbered MX record points to local host
2010-10-11 10:51:20 lowest numbered MX record points to local host: mydomain.org (while verifying <username1@mydomain.org> from host outappmail001.snc4.facebook.com (mx-out.facebook.com) [66.220.144.155])
2010-10-11 10:51:20 H=outappmail001.snc4.facebook.com (mx-out.facebook.com) [66.220.144.155] F=<update+zrdov1ll=icf@facebookmail.com> temporarily rejected RCPT <username1@mydomain.org>: lowest numbered MX record points to local host
2010-10-11 10:56:24 lowest numbered MX record points to local host: mydomain.org (while verifying <username1@mydomain.org> from host outappmail001.snc4.facebook.com (mx-out.facebook.com) [66.220.144.155])
2010-10-11 10:56:24 H=outappmail001.snc4.facebook.com (mx-out.facebook.com) [66.220.144.155] F=<update+zrdov1ll=icf@facebookmail.com> temporarily rejected RCPT <username1@mydomain.org>: lowest numbered MX record points to local host
2010-10-11 10:56:24 lowest numbered MX record points to local host: mydomain.org (while verifying <username1@mydomain.org> from host outmail002.snc1.tfbnw.net (mx-out.facebook.com) [69.63.178.161])
2010-10-11 10:56:24 H=outmail002.snc1.tfbnw.net (mx-out.facebook.com) [69.63.178.161] F=<confirm+AY2FwdGFpbkBzYWZlZW5hLm9yZw@facebookmail.com> temporarily rejected RCPT <username1@mydomain.org>: lowest numbered MX record points to local host
2010-10-11 10:56:29 lowest numbered MX record points to local host: mydomain.org (while verifying <username1@mydomain.org> from host mail-qy0-f175.google.com [209.85.216.175])
2010-10-11 10:56:29 H=mail-qy0-f175.google.com [209.85.216.175] F=<usernname2@gmail.com> temporarily rejected RCPT <username1@mydomain.org>: lowest numbered MX record points to local host
2010-10-11 10:57:21 lowest numbered MX record points to local host: mydomain.org (while verifying <username1@mydomain.org> from host mail-qw0-f47.google.com [209.85.216.47])
2010-10-11 10:57:21 H=mail-qw0-f47.google.com [209.85.216.47] F=<usernname2@gmail.com> temporarily rejected RCPT <username1@mydomain.org>: lowest numbered MX record points to local host
2010-10-11 10:57:49 lowest numbered MX record points to local host: mydomain.org (while verifying <username1@mydomain.org> from host mail-qw0-f47.google.com [209.85.216.47])
2010-10-11 10:57:49 H=mail-qw0-f47.google.com [209.85.216.47] F=<usernname2@gmail.com> temporarily rejected RCPT <username1@mydomain.org>: lowest numbered MX record points to local host
2010-10-11 10:58:19 lowest numbered MX record points to local host: mydomain.org (while verifying <username1@mydomain.org> from host outmail026.snc1.tfbnw.net (mx-out.facebook.com) [69.63.178.185])
2010-10-11 10:58:19 H=outmail026.snc1.tfbnw.net (mx-out.facebook.com) [69.63.178.185] F=<confirm+AY2FwdGFpbkBzYWZlZW5hLm9yZw@facebookmail.com> temporarily rejected RCPT <username1@mydomain.org>: lowest numbered MX record points to local host
2010-10-11 10:58:25 lowest numbered MX record points to local host: mydomain.org (while verifying <username1@mydomain.org> from host outmail021.snc4.facebook.com (mx-out.facebook.com) [66.220.144.153])
2010-10-11 10:58:25 H=outmail021.snc4.facebook.com (mx-out.facebook.com) [66.220.144.153] F=<confirm+AY2FwdGFpbkBzYWZlZW5hLm9yZw@facebookmail.com> temporarily rejected RCPT <username1@mydomain.org>: lowest numbered MX record points to local host
2010-10-11 11:00:31 lowest numbered MX record points to local host: mydomain.org (while verifying <username1@mydomain.org> from host outappmail001.snc4.facebook.com (mx-out.facebook.com) [66.220.144.155])
2010-10-11 11:00:31 H=outappmail001.snc4.facebook.com (mx-out.facebook.com) [66.220.144.155] F=<update+zrdov1ll=icf@facebookmail.com> temporarily rejected RCPT <username1@mydomain.org>: lowest numbered MX record points to local host
2010-10-11 11:02:33 lowest numbered MX record points to local host: mydomain.org (while verifying <username1@mydomain.org> from host mail-qw0-f47.google.com [209.85.216.47])
2010-10-11 11:02:33 H=mail-qw0-f47.google.com [209.85.216.47] F=<usernname2@gmail.com> temporarily rejected RCPT <username1@mydomain.org>: lowest numbered MX record points to local host
2010-10-11 11:03:22 lowest numbered MX record points to local host: mydomain.org (while verifying <username1@mydomain.org> from host outmail018.snc1.tfbnw.net (mx-out.facebook.com) [69.63.178.177])
2010-10-11 11:03:22 H=outmail018.snc1.tfbnw.net (mx-out.facebook.com) [69.63.178.177] F=<confirm+AY2FwdGFpbkBzYWZlZW5hLm9yZw@facebookmail.com> temporarily rejected RCPT <username1@mydomain.org>: lowest numbered MX record points to local host
2010-10-11 11:03:28 lowest numbered MX record points to local host: mydomain.org (while verifying <username1@mydomain.org> from host outmail022.snc4.facebook.com (mx-out.facebook.com) [66.220.144.154])
2010-10-11 11:03:28 H=outmail022.snc4.facebook.com (mx-out.facebook.com) [66.220.144.154] F=<confirm+AY2FwdGFpbkBzYWZlZW5hLm9yZw@facebookmail.com> temporarily rejected RCPT <username1@mydomain.org>: lowest numbered MX record points to local host
2010-10-11 11:05:34 lowest numbered MX record points to local host: mydomain.org (while verifying <username1@mydomain.org> from host outappmail001.snc4.facebook.com (mx-out.facebook.com) [66.220.144.155])
2010-10-11 11:05:34 H=outappmail001.snc4.facebook.com (mx-out.facebook.com) [66.220.144.155] F=<update+zrdov1ll=icf@facebookmail.com> temporarily rejected RCPT <username1@mydomain.org>: lowest numbered MX record points to local host
2010-10-11 11:06:26 lowest numbered MX record points to local host: mydomain.org (while verifying <username1@mydomain.org> from host outappmail001.snc4.facebook.com (mx-out.facebook.com) [66.220.144.155])
2010-10-11 11:06:26 H=outappmail001.snc4.facebook.com (mx-out.facebook.com) [66.220.144.155] F=<update+zrdov1ll=icf@facebookmail.com> temporarily rejected RCPT <username1@mydomain.org>: lowest numbered MX record points to local host
2010-10-11 11:06:27 lowest numbered MX record points to local host: mydomain.org (while verifying <username1@mydomain.org> from host outmail024.snc1.tfbnw.net (mx-out.facebook.com) [69.63.178.183])
2010-10-11 11:06:27 H=outmail024.snc1.tfbnw.net (mx-out.facebook.com) [69.63.178.183] F=<confirm+AY2FwdGFpbkBzYWZlZW5hLm9yZw@facebookmail.com> temporarily rejected RCPT <username1@mydomain.org>: lowest numbered MX record points to local host