The Ticketleap Merchant Account, Ticketleap Payments and Authorize.net both support iOS onsite sales for devices running iOS 11 and higher. If you are currently using PayPal as your payment provider, you will have to switch to the Ticketleap Merchant Account or Authorize.net to sell tickets onsite.
You can do that by hovering over Settings and clicking Payment Processing from the Ticketleap dashboard.
On the Payment Processing page you can choose to use the Ticketleap Merchant Account, Ticketleap Payments or Authorize.net. These are the same steps you took when you initially told Ticketleap how you want to be paid.