Try full email as username? Just a guess
Joeblow@Gmail.Com
Etc
Yes of course i use that.
I actually found the issue today.
With Gmail its compleetly necessary to use (StartTLS) and the only port that works is 587.
took me like 7 hours of testing before finding this out

Yahoo never worked and not my ISP either. The strange is that yahoo worked on my dcs-933l camera, and the exact same settings it had did not work with the dcs-2230. Thats confusing.
So for some other ppl with troubles:
My setup now is:
Sender email address: emailname@gmail.com
Recipient email address: differentemailname@hotmail.com
Server address: smtp.gmail.com
User name: emailname
Password: gmail email password
Port: 587
This server requires a secure connection (StartTLS): startls ON