Hey, i know we 're in 2018This answer can help you in any osTicket version.You just need to login in your email (email you want to send messages) and check settings, for exemp:I use too gmail, so i need to login>open setting in left corner>configurations> now look for filter -->forwarding and POP/IMAP> make sure you allow both!Finally, last step and more important, open your icon and go to "My Account" > sign-in & security> Scroll everything down and you'll see "allow less secure apps" and done!Have a nice day!