You haven't really provided us with much information regarding your problem, so I'm not real sure what to tell you.You haven't told us the version of osTicket your running, what your mail setup is (mail server software, spam filter software/hardware, delivery method to osT), and what email client you used to send/receive, what method your using to send email from osT (phpmail, smtp).As I stated previously, I have never seen this happen and I do not recall this sort of issue being reported before. I would recommend that you attempt to use the search feature to see if anyone else reported what a similar issue (or check github) and see if their setup is similar to yours, and/or what their solution was.