Webstart Workstation gets "Connection Refused" when connects to MOM.

Webstart Workstation connects to  Collector EMs without any issue.

Webview connects to MOM without any problem. 

Possible causes: 

1. connectivity
2. Port
3. firewall
4. proxy
5. DNS

CA APM 10.7 SP3
RHEL 6.0

1. Make sure the computer can ping telnet using the same port
2. Check the firewall 
3. Make sure the Proxy settings 
4. Check any changes on the DNS