But if I am using Wifi, how is SMTP settings of Cellular service provider going to help? While receiving the mail it always works. The problem is only while sending the mail although in Outgoing SMTP Servier I have specified "smtp.gmail.com".

The same setting is with my Microsoft Outlook also, which I use for my gamil account at home.

What I didn't understand is, for each and ever connection (the wifi list that it shows) and mObile office it ask for different settings in SMTP server.

Afterall its internet. so should'nt there be a common SMTP Server for gmail ??