Mail delay issues affecting 1 account [5.0.4]

[MOlin]

Help,

Issue affecting only 1 user: user gets some emails immediately, others take minutes or hours? Emails are sent from same internal domain (employee to employee). Attachments don't seem to make a difference. Header data does not give a clue, or any delay "received:" headers show no delay?

Any clues on where to look? TIA! -Mike

Release 5.0.4_GA_2101.MACOSXx86 NETWORK edition, client 10.4.11, firefox 2.0.0.12

[uxbod]

Try tracing the message using CLI zmmsgtrace - Zimbra :: Wiki also check in /var/log/zimbra.log any error messages.