Client is running SBS 2008 and Exchange 2007 SP3. All patched and up to date. Several iPhone / Android users on domain.
iPhone users have had occasional sync issues that were rectified by either password change or remove/re-add account on phone, or remove device partnership in Exchange or OWA interface.
One user started having sync issues with iPhone (4S, iOS 8.3). None of the usual tricks worked. I noticed that the user had 7,000 UNREAD messages in his inbox and had him pare it down (to about 800). No luck. (Mailbox went from about 15GB to abou 6GB).
The account gets added to phone successfully, but the iPhone just throws up the 'Cannot Get Mail. Connection to the Server failed' message. Samsung creates account as well but just shows his inbox folder (no subfolders) and it remains empty.
OWA works fine. Outlook works fine on PCs at office and from his laptop (in office or outside).
I tried creating a temp folder and moved a lot of mail from inbox to temp folder. No help.
I'm thinking it is something with his mailbox (not his phone), since I also cannot get his account to sync on my iPhone 4S, nor can I get it to sync on a Samsung S5. Other accounts on same domain can be added to either phone without issue.
Was thinking of changing his username to see if that helps, but if it is his mailbox, not sure how to proceed. I've read that export to PST and import to new account might cause calendar, recurring appointments, email autofill,etc. to get messed up.
Any recommendations on how to resolve?