Two Exchange email accounts in Outlook - one doesn't send correctly

Question

Hello. I currently have two Exchange email accounts added to my Outlook 2010.  The second email is shared by a fellow coworker.  Since I added the second account, I've received synchronization errors in my Unread folder.  Normally,
I've ignored these as there wasn't any actual functionality errors with Outlook.
Once in a blue moon though, the sync errors stop and I'm no longer able to email from/as that second email.  Instead, it simply gets stuck in the Outbox where it never actually goes through.  In the past, I've done a mish-mash of using the Repair
Tool on both OST files and clearing offline items for both Inboxes.
I was never actually sure if either of the above methods was the actual fix but Outlook eventually let me send emails again from the second account (and once more resuming the flow of synchronization errors).  Now though, it seems like neither
of those remedies actually work anymore.  
I've searched online to no avail of what might be the cause of this.  Is anyone familiar with what might be going on?  I'm guessing part of the issue is because the second email is shared between two people and across multiple devices?

Answer 1

Hi,
What synchronization errors have you received? The only thing I can think of on Exchange side is
Open Item Limit or Session Limits.
On outlook client side, this issue can be caused by numbers of possibilities such as Addins/the outlook profile.
And your two methods (clearing offline items will clear items from local .ost file) are related to OST files, so I suggest to create a new .ost file and synchronize the folders by the following steps:
Exit Outlook.
In Control Panel, click or double-click Mail.
On the E-mail tab, select the Exchange account, and then click
Change.
Clear the Use Cached Exchange Mode check box.
Click More Settings.
On the Advanced tab, click Offline Folder File
Settings.
Click Disable Offline Use, and then in the dialog box that appears, click
Yes.
Again, click Offline Folder File Settings.
Click OK.
In the dialog box that appears, click Yes.
Under Cached Exchange Mode Settings, select the Use Cached Exchange Mode check box.
Click OK, click Next, and then click
Finish.
In the Account Settings and Mail Setup dialog boxes, click
Close.
Start Outlook, point to Send/receive on the Tools menu, and then click
Send/Receive All.
In addition, we should check this issue via OWA.
Also make sure that your account is not downloading the cache of the shared mailbox. Go to
account settings in outlook, more settings ->
advanced tab and uncheck download shared folders. Restart Outlook.
If this issue persists next time, I suggest to post on
Outlook Forum for more professional help about Outlook client side issue.
Best Regards.