IMAP Server Hangs

[Greenview]

We have an issue where the IMAP server will allow log-ins, but not examine messages in folders. This causes the session to hang and we eventually reach our IMAP thread max while clients are waiting for the session to close. Here is an example session:

# telnet mail.domain.com 143
Connected to mail.domain.com.
Escape character is '^]'.
* OK mail.domain.com Zimbra IMAP4rev1 server ready
. login test@domain.com ******
. OK [CAPABILITY IMAP4rev1 ACL BINARY CATENATE CHILDREN CONDSTORE ENABLE ESEARCH ESORT I18NLEVEL=1 ID IDLE LIST-EXTENDED LIST-STATUS LITERAL+ LOGIN-REFERRALS MULTIAPPEND NAMESPACE QRESYNC QUOTA RIGHTS=ektx SASL-IR SEARCHRES SORT THREAD=ORDEREDSUBJECT UIDPLUS UNSELECT WITHIN XLIST] LOGIN completed
. LIST "" "*"
* LIST (\HasNoChildren) "/" "Chats"
* LIST (\HasNoChildren) "/" "Contacts"
* LIST (\HasNoChildren) "/" "Drafts"
* LIST (\HasNoChildren) "/" "Emailed Contacts"
* LIST (\HasNoChildren) "/" "INBOX"
* LIST (\NoInferiors) "/" "Junk"
* LIST (\HasNoChildren) "/" "Junk E-mail"
* LIST (\HasNoChildren) "/" "Sent"
* LIST (\HasNoChildren) "/" "Trash"
. OK LIST completed
. examine "INBOX"

The examine results in the session hanging. This is happening for all clients connecting via IMAP. POP3 and Activesynce are NOT affected.

Has anyone experienced this before? Any insight would be greatly appreciated.

Thanks!