I am using OsTicket version 1.14.3 on a GoDaddy hosting and when I send emails to domains @ gmail.com to the client they arrive correctly but if I send them to @ outlook.com or @ hotmail.com they do not even reach the folder of unwanted mail.
IF using a single account you can send email to one address (gmail) but not to another (hotmail) then the problem is likely not with the account (or email client) of the sender. Otherwise you would not be able to send to the first address also.
