clicking on "sendtestmail" it is not sending

Below are my observations and please make sure to fix it

 

1) As button type is 'submit' you make sure to have a form tag. When button click, it will submit the form.

2)  In Ajax call, you no where sending email information also your content-type is 'contentType: "application/x-www-form-urlencoded; charset=UTF-8",' which is supposed to use for uploading the files.

 

 Please correct the above.