Having trouble connecting to any server on real ip address. Whenever i try connecting to servers it responds like

* Connecting to irc.ca.us.mibbit.net (6667)
-
* Unable to resolve server

although it works well on VPN, Proxy and fake ip addresses. I don't understand if I'm making any mistake or something went wrong with the settings. Please help.

If you bring up a command prompt and issue nslookup irc.ca.us.mibbit.net does it resolve? If not, you have some network issue - not mIRC related.