Invalid name or cannot reach server

I am an independent contractor and have been tasked with using Spark 2.5.8 in conjunction with a corporate server running Wildfire (I believe). I enter my access name and password, the server name, and get the error noted in the title above. Port is 5222. The IT guy is baffled, but I believe this system is new to him. Any suggestions as to what I can try to do locally to get a connection? If this is not my problem (and I don’t think it is because I use xmpp protocols with no problem, ie, Trillian and AIM, Google Talk, etc.), any suggestions I can pass along to IT?

I am running a NAT router, if that helps. Should I look into port forwarding? Windows XP. I haven’t changed anything under the Advanced tab. Any other info I can give, just let me know. I appreciate any replies in advance. Thank you!

I wonder if that server is accessible by servername. Maybe you can found out its IP and try putting it in Server field.

wroot, thanks for that info. It led me to a solution.

I had once installed zonealarm on my system. Even though I did not have it running (so I thought), when I went to uninstall it just as a random idea, I was surprised to see it “shutting down.” I had no idea it was running in the background somewhere. Anyway, completely uninstalling it did the trick, and I also added the hostname and IP to my hosts file, which is where your suggestion helped me. Thank you!