Email sometimes have significant lag time between send and recieve on same server

Email sometimes have significant lag time (couple of hours) between send and recieve on same server. The log shows that the router delivered the message moments after being sent but the email did not show up in the recipients mailbox until a few hours later. This rarely happens but does so often enough to make it seem legit. Has anyone seen this before? Any ideas why this happens?

Thanks,

Daniel

Subject: Email sometimes have significant lag time between send and recieve on same server

How do you know? Do you wait for the mailbox notification? If so the setting might be wrong. Is the users mailbox local or not? If so replication might be the issueWhat are the indexing settings on the user’s mailbox? Maybe the index is not refreshed regularly enough so the mail is not showN?