You have not given us enough information about your setup and work flow to even begin to troubleshoot this. Or even provided the version of osTicket you're talking
about. Please help us to help you by reading and following the posting
guidelines located in this thread: Please read before requesting assistance. The more information you give us the better we will be able to assist you. Thank you.The first thing that I personally would check is the email client delay timer between polls. (This varies greatly by client)