[Exim] Missing Emails - no immediate delivery

This is a multi-part message in MIME format.
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+++ 19PGnp-0005lQ-00 not completed +++
2003-06-09 15:10:51 19PGnp-0005lQ-00 <= a1@??? H=localhost.localdomain
(example.com) [127.0.0.1] P=smtp S=763 id=45748.211.24.136.34.1055142650. squirrel@???
2003-06-09 15:10:51 19PGnp-0005lQ-00 no immediate delivery: load average 20.02

+++ 19PGnj-0005kU-00 not completed +++
2003-06-09 15:10:45 19PGnj-0005kU-00 <= a1@??? H=localhost.localdomain
(example.com) [127.0.0.1] P=smtp S=763 id=45747.211.24.136.34.1055142644.squirrel@???
2003-06-09 15:10:45 19PGnj-0005kU-00 no immediate delivery: load average 20.28



This is part of my exim mail server logfile when i tried to send email out of a1@??? , the email is not received by the
recipients and it just end up there.

Do you guys know what causes the problem here ?

and is there any way to tackle it?

Thank you
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