When I set the mail I input the information to these areas with a working email in gmail account:

Store Admin Email:     
Store Admin Email Display Name:   
Host:   
Port:   
User:   
Password:   
Enable SSL:   
Use default credentials:   


I checked "Enable SSL" and leaved "Use default credentials" unchecked.

But it didn't work when I test it. The error message is as the following:

"Request for the permission of type 'System.Net.Mail.SmtpPermission, System, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089' failed."

The only problem I think is "Port" which I got from my gmail account "Setting--Thunderbird--Outgoing SMTP". I also tried the Port 587 from another post. It didn't work either.

What is the problem?