pop3 is port 110 not port 25.. the server is responding on the pop3 port..
$ telnet pop.net4india.com 110
+OK POP3 Ready popproxy1.net4india.com 0001e993
+OK USER guest set, mate
-ERR Could not determine server
Obviously since I don't have an account I can't login..
Verify your username and password.. maybe give them a phone call..