I am getting the error "Sending Email failed. Please enter the correct mail server,port or admin email" upon providing the following into Mail Configuration 

Mail server : smtp.gmail.com

Port :  I tried 587,467 and 25 value for the port

Admin email : It is my personal gmail account address

Username : left it blank and also with gmail account address

Password : left it blank and also with gmail account password

Test Mail : It is my personal gmail account address same as admin email

with mailconfig.properties with the following values true and false

mail.smtp.starttls.enable=false
mail.smtp.auth=false

But got the following error 

Please provide suggestion to fix  error "Sending Email failed. Please enter the correct mail server,port or admin email" in order to successfully generates Test Mail through Auto Pass License Server