Good evening Lisa and welcome to the Events Calendar Support forum!
Thank you for reaching out to us.
We are sorry to hear about the tickets not sending.
I would love to help you with this topic.
Would you mind sharing what message you are getting as a failure response ?
Secondly, when you go to Settings > Easy SMTP and try out the test email functionality, does that work ?
Finally, can you tell me what your settings are at the very bottom of the Events -> Settings -> Tickets screen (perhaps sharing a screenshot would be simpler) ?
Hang in there!
Geoff B.