Event ID: 20209 Source: Blackberry Dispatcher

Event Type: Warning
Event Source: Blackberry Dispatcher servername
Event Category: None
Event ID: 20209
Date: xxx
Time: xxx
User: N/A
Computer: xxx
{Blackberry user's name} DecryptDecompress() failed, Tag=393289, Error=604

This message indicates that the user specified in the event description has had their encryption key expire and it needs to be regenerated.

On the specific user's blackberry device, go to OPTIONS > SECURITY
Or on newer models, go to GENERAL SETTINGS.

Scroll down to the "Services". Highlight "BlackBerry [sXXXXXXXXX] (3DES)".
Press the track wheel
select "Regenerate Encryption Key"