Question...
Is the email address that you are sending to, the same as the one that you are using to send?
If so... then that is the problem.
You have it set up to collect email from it.
Emailing itself would create a ticket.
Creating a ticket would email you.
repeat. endless loop.
osTicket will prevent that by not sending the email.
If not then I would recommend that you reach out to your email provider and see if they can look at the logs.
Maybe they are blocking the email from being sent for some reason (likely they think its spam).
They should also confirm that the system is connecting to the mailserver attempting to send the emails in the first place.
Alternatively, some mail servers still let people telnet to them.
You could google how to test a mail server with telnet and go through the step yourself.
connect to server, authenticate, give it a mail message to send, and see if you get the email your sending.