I always prefer my gmail account from any other mail service provider in the Internet. But when I started to encounter problems sending e-mails or even replying to messages, I thought of deleting my gmail account.

The error message is like this:

Error
Oops… a server error occurred and your email was not sent. (#707)
Then, instantly I Googled it and find no solution at first.  There were minimal replies or suggestions that would tackle the error message #707. Some person in the forums said, “Disable Google Buzz.” I wouldn’t want to because I’m establishing my profile to be able to optimize searchability of my blog.
I let days passed hoping that it would just go away, pending all my e-mail replies.  I even started migrating the contacts to my yahoo mail.
I rarely click ‘Help’ button to any website I log or browse in.  Now, I hit the button ‘HELP’ in Google. To my dismay, I found no result specifically to error #707.
Finally when I tried using https instead of http, voilà the message was sent.  I do not really know what’s the difference of using https.  All I know is it helps solving error #707.

https://mail.google.com/mail/?ui=1&ov=1

This link is also the older version of gmail.