Jabber Server

Hello, (sorry for this semi long text, but I wanted to explain the working environment completely).
I've a problem on working with Jabber. We've installed a package named "Wildfire 2.4.4" on our server & use the "Spark" software as the client to connect to the server (both of them are available here: http://www.jivesoftware.org/downloads.jsp).
We defined "110" port number (default is the POP3) as the normal connection port & 5050 port number for SSL communications (we didn't find any other useful & open port to do this & the comfort ones has been filtered on our server. Too, the jabber data is in the CELL mode, so they must stick onto the other packets. So we must define a open port to connect to).
We created some testing users, then went to the spark and entered the username and password & set the Host as our server & set the port as 110 (with no SSL Connection attempt), by the time we clicked on the login button, we got into & apparently we were logged in.
Next day, I wanted to connect to the server, but I said "Invalid User Name or Password", whereas my friends can log in with my user.
I checked the firewall status and process, but didn't find any thing around this. Even I sniffed my network traffic to see if packets are being misidentified or manipulated or get lost, but didn't find anything related to the Jabber too.
I checked my connection speed. It's in a good state. But while working with the Jabber, no packet gets sent or received, while the previous day it wasn't such so.
I pinged our server & got responses. I checked the port 110 on server on my PC and it said it's open.
Now, please help and tell me what's the problem & how to connect with my messenger to the server.
I think there is firewall or IDS that block the traffic on the port 110 (I used proxy servers and failed too). But if be so, how did I connect to my server in the previous day !?

I'm waiting for your answers and approaches.
Thanks anway