Why do some emails get to one user late?

It's quite strange that one of my users sometimes (not all the time) got some (not all) of his emails several hours late, as compared to the very same emails got to other users in the list of "TO:" group. How could that happen? And why?
Could it be because his email box is too big (3 Gig) or what? Please help.
We are on Exchange 2010 and this user on Outlook 2007.
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More details please, what kind of Exchange setup do you have?
CastlewoodAuthor Commented:
We have a single Exchange server with about 50 mailboxes. All users use Outlook 2007.
could you post the output of a test at:
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If it's possible to "know" when this happens, I'd have the user login to OWA and see if the email is there.  Wondering if this is an Outlook vs Exchange issue.

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As i mentioned above, use www.testexchangeconnectivity.com, mxtoolbox.com and a telnet test would give you a good idea. I'd also check the queue to see if there are any stuck messages and why.

You could also try re-creating your connector.

CastlewoodAuthor Commented:
dexIT, can you tell me which test you want me to run? Is it "Microsoft Office Outlook Connectivity Tests" ?

Under Microsoft Office Outlook Connectivity Tests, input your info and post the results.
It would also be worth performing an inbound SMTP email test as well to see if we can replicate the issue, monitor the queue as you're performing this test.
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