CAUSE 3: Licensing issue.
Ensure the format and port being used is the same on the client and the SSB.
Go to Basic Settings | System
Under Service Control Make sure that Enable is greyed out like below:
Install the correct license that matches the syslog version or SSB version.
USEFUL TROUBLESHOOTING COMMANDS:
On the client run tcpdump -vv -i any -A port PORTNUMBER
On the SSB run: netstat | grep LISTEN