Outlook will connect to one account but not another (Same Exchange server)

Can you make a new Outlook Account Profile for the problem computer / account?  Everything else seems in order.

Are these two accounts running under the same profile in outlook?  I'm assume so, as nobody want to close outlook just to look at a different mailbox.
It sounds like BOTH mailboxes connect at first, and only sometime later disconnects just the helpdesk?  This leads me away from profile and permission issues, which usually either let it work or not, as opposed to the intermittent issue you are having.  (Then again, John's suggestion to create a new profile wont take long, and is a good sanity check)

I notice that your screen-shot shows a DIFFERENT server name for the helpdesk account-  it is not a FQDN "FULLY QUALIFIED DOMAIN NAME" (the stuff after the first dot, makes it "fully qualified").  My question would be where is this name coming from, and why is it different?  I would suggest making sure your outlook config uses the FQDN, and double check DNS settings on the client machine.  DNS Test: if you "ping cpcexserver" from the workstation  (and DNS is properly configured), it SHOULD return the FQDN along with the ping results, does it?

Korbus, Yes you are correct it does connect when I first open outlook its a seemingly random interval later that it disconnects.
I do believe I have created a fresh profile in my testing but I have done that again for the sake of this diagnostic. But I have to agree it seems unlikely considering the circumstances. We've also had this problem on other workstations so its not even just one profile.
Regarding the FQDN, this is the main question that baffles me. Yes when I ping cpcexserver it responds back with the FQDN, I actually added this CNAME to DNS recently but cpcexserver always pinged back to IP. (We had the unfortunate job of taking on a multi domain system one AD for Windows login and another for Email.)
Again, i have confirmed in Control Panel > Mail that both accounts have the FQDN in the connection server. How on earth is it that one connects to one server name and the other account another!!

So we have this similar setup on two other team members workstations. They have their work email account and the Helpdesk account in outlook 2010. In addition to that, I have come across this issue on other users' workstations. Where they call in and say their outlook is disconnected. This is why I had added that cname. I thought it was a DNS issue. That just reminded, when I did that, my Helpdesk account was disconnected at that moment. Upon adding the cname Helpdesk connected. I thought, great that's what it was. It couldn't translate the name. But later on the account disconnected again. So I decided to post here...

I try to switch the primary account and monitor behavior. That's a good test... I'll post back.

Korbus, I have switched the primary accounts and it has been a week since and Outlook has not disconnected. I would like to try to shed some light on why this might happen for uses who come across this post in the future. Can you explain why you asked me to perform that step and what might make that fix work.
Thanks Korbus!

Just to confirm what you mean by  "I have switched the primary accounts":  You configured outlook to use the help-desk account as the primary account in outlook, it no longer disconnects?  Even though the user is still logged on onto windows with their regular user name.  Is this right?

The purpose of making this change was simply to test the result.  This confirms a few things for us:  we know that the user does indeed have the correct permissions to access this mailbox.  We now know the mailbox is not corrupted nor malfunctioning.  We know the PC has a good connection to exchange.

What might make the fix work:  I'm honestly not sure WHY that got it working again, but here are some possibilities:  rebuild of corrupted outlook profile.   I have seen many outlook profiles get corrupted, and it's possible this is what happened to your initial setup, and it was "fixed" by creating a new one.  (Though the fact that this occurs for multiple users implies (but is not proof) AGAINST this theory).  If this IS indeed the cause, creating a NEW profile with the help-desk account as secondary should ALSO work.
Dang, I had another possibility in my head a moment ago but lost it... I'll post back if I can remember it.  
Hopefully some other experts will have additional insights on what else this test indicates.

But, lets see if we can get it working properly (user's mailbox is primary in outlook, help-desk secondary) before you select a solution.  (not that I have any other ideas at the moment, other than creating another new profile)

Hey Korbus, yes you are correct. I switched the primary to the help desk. I actually recently installed Win 8.1 and this issue went away. Now as I stated previously, I tried deleting and recreating my windows user profile to no avail. So this must have been something specific to the installation on that workstation (actually a Parallels VM). Im not sure we are ever going to get to the bottom of this one. especially being that I have now changed VM's.  However before I blew away the old VM I did switch back the primary account to mine. I used it like this for about a week and it was fine! WTH is that!!!!

I am awarding you points because I would not have ever thought to switch the primary account. It didn't necessarily bring us to the exact cause but nonetheless it was a solution to my problem.

Thanks Korbus!

Excellent test! Ultimately we never discovered the cause of this issue. But this was a solution.