What causes Blocked Worker Thread error messages?
There are multiple reasons for blocked MAPI worker threads.
* The BlackBerry Enterprise Server attempted to contact a BlackBerry device user's mailbox but could not initiate a connection with the Microsoft Exchange Information Store.
* The BlackBerry Enterprise Server attempted to contact the Microsoft Exchange server and is still waiting for a response.
* The Microsoft Exchange server might be offline or another unreachable state.
* The BlackBerry Enterprise Server attempted to contact the Microsoft Exchange server but did not receive a timely response. This could be due to issues such as packet loss on the network or complex calls to the Microsoft Exchange server (e.g. a bulk load on a BlackBerry device user with more than 5000 calendar entries).
* The Microsoft Exchange server may be taxed too heavily and cannot handle the load.
After the cause has been determined, it will probably be necessary to restart the BlackBerry Enterprise Server. After a pool of threads has crashed restarting the BlackBerry Enterprise Server services will not release them, as they are part of the Messaging Application Programming Interface (MAPI) subsystem.
Important: Restarting the BlackBerry Enterprise Server will delay message delivery to BlackBerry devices. For more information, see KB04789.
If only individual threads are hung, restarting the BlackBerry Enterprise Server services will release those threads and reinitialize them without restarting the BlackBerry Enterprise Server. However, since it is difficult to determine whether individual threads have crashed, or an entire pool of threads, it is better to restart the BlackBerry Enterprise Server rather than restarting only the services.