You have created an amazing software for everyone to use.
It simply Rocks !!
The problem is that You've limited the number of Port (in case of SMTP settings) to 100
But to support Gmail , which has the default post number for SMTP as 465.
Secondly there should be an option to Enable SSL
so that the software works with Gmail flawlessly
In all you have an amazing software, in case you make the changes above it will turn out to be even better.
With Warm Regards,