To Test Whether you have Added the Correct SMTP Details in "Email Setup".
Type Receiving Email, Subject, Message and Click on "Submit".
After Submitting, if you see Message : "Email Sent Successfully !", then you have Added Correct SMTP Details in "Email Setup" else you need to check it and Update.
If you are able to receive mail without issue, but are unable to send mail from SMTP Test and you are certain your outgoing mail server settings are correct, you might be blocked by your ISP from connecting on port 25.