AD user is created, but not mailbox is create.

Whne you created the user did you get the prompt to create a mailbox?
If so then you should check your recipient policy.  Thats what controls email addresses attaching to mailboxes when created.

I made sure that box was checked and even made sure that i was selecting the proper server. I even checked our other Exchange server, and it wasn't there either.

I've double checked the policy it looks fine, it hasn't changed since the last user and mailbox was created.

Does the mailbox come up in System Manager?

Nope.

Can you right click the user in AD and choose exchange tasks and create a mailbox?

The options i have available to me are:
Move Mailbox
Delete Mailbox
Configure Exchange Features
Remove Exchange Attribuites

Interesting - when you go into ADUC and double click a user - the email address tab should be available.
Click it and there is probably no email address there.
Add the email address manually.

If this is all accurate so far then the recipient update policy failed for some reason

The email list was empty, so i manually populated it. Still no luck.

Now to ensure i am doing this correctly i did a little sanity check. I created another new user, but created their mailbox on our other exchange server, and it worked just fine.

Also, when i log on as my new user (the one who's not working) and attempt to configure Outlook, i get the following message when i Check the user's name:

The name could not be resolved. The name could not be matched to a name in the address list.

For this user is hide email address from exchange list checked?
Have you created a new user on this 'broken' server to see what happens?

Hi,

Manually populating the email address tab is not recommended. You need to troubleshoot good old RUS. The Recipient Update Service is responsible for stamping the new account with the correct Exchange attributes when this is not working you get exactly what you are seeing. Have you changed any domain controllers or anything else recently.

Go through these articles: -
Troubleshooting the Recipient Update Service (RUS) using Event Logs
http://msexchangeteam.com/search/SearchResults.aspx?q=rus

So something i have just noticed. It doesn't look like the domain controllers are talking like they are supposed to. Lets call the site that isn't working Site B. This is a remote site, while Site A is our primary site with the main exchange server.

I created an account using a Site A server, to connect to Site A exchange, it worked.

I created an account using a Site B server, to connect to Site B exchange, it did NOT work.

I created an account using a Site A server, and attempted to log onto a Site B computer, it did NOT work.

The other day i organized the domain controllers into two different sites. This probably about the time all of this stopped working, don't know why i didn't think of it sooner. So obviously the controllers at the different sites are not updating each other properly, but the connection between offices is working.

Where should i start looking in the AD Sites and Serv?

AD sites and services shouldnt affect it.
As mass2612 suggested I would look at the RUS troubleshooters
http://www.msexchange.org/articles/Troubleshooting-Exchange-Recipient-Update-Service-RUS.html
http://support.microsoft.com/kb/822794/en-us

I haven't had a chance to look through the troubleshooters yet, but i will. I went to lunch, came back and was able to configure outlook for that account. After outlook successfully finished, it the mailbox was created in ESM. So there's something causing a major delay in the updates.

I will review the RUS troubleshooters now, thanks a lot for the help.

Sounds like you have RUS running in one site which is quite normal. However it can lead to delays when creating mailboxes in the remaining sites. You can implement RUS in the other sites as well which can improve the performance in relation to speed.

The mailbox will not show up in ESM until either an account logs onto the mailbox or a mail is sent to the mailbox. That's why you couldn't see it there originally but you could not log on or send mail to it as RUS had not stamped the account with the Exchange attributes yet.

More un RUS: -
Troubleshooting the Exchange Recipient Update Service (RUS)
http://www.msexchange.org/articles/Troubleshooting-Exchange-Recipient-Update-Service-RUS.html

Is this the only server in the domain ?if not just check the AD replication ok or not.

I had similar problem before found AD replication problem between servers caused the problem
run
repadmin /showrepl
on the server where you are not able to create mailbox. Reply back with the result

Sorry for the delay in this post, it has been a busy past few days.

I've gone through the troubleshooting guides and i haven't been able to find event 8011 with "Base DC" in the description. One of the articles states, "the Recipient Update Service may be waiting for a domain controller to return search results". As far as i can tell RUS is still functioning properly.

We didn't have this problem until I organized the domain controllers into different sites, so it could be possible that there is a communication problem because it takes a while for the exchange account to be created. About an hour or two after the account is created, the email account appears and works.

Syed_riz2008,
In response to your question, there are two Exchange servers, both at different physical sites, and both are domain controllers. Below is the information from the repadmin command.

The site that seems to be working has the primary exchange server and is basically our HQ, while the site not working has a secondary exchange server.
repadmin.JPG

When i configured the ADSS, there was one thing that I'm not totally convinced is configured properly.
Under:
Sites > Inter-Site Transports > IP

I still have the DEFAULTIPSITELINK which has both sites in it and replicates every 180 minutes and a cost of 100. The instructions i followed had me configure a new one for my connection. I have a T1 with 1024Mb of bandwidth between both sites. The new object also has a cost of 100 but replicates ever 24 hours.

Could this be causing the problem?