Edit the templates/streams file to replace with your ngrok host. Example: wss://abcdef.ngrok.io/streams. Remember to use wss:// and include /streams in the url
Go to your Twilio page where you manage your phone number. Under the Configure tab, replace the webhook URL where the call comes in to your ngrok url. Example: https://abcdef.ngrok-free.app/twiml . Remember to use https:// and include /twiml
The usage of .ngrok.io vs .ngrok.app interchanged within the application can lead to confusion for the user on which URL to use.
In the readme, the documentation states using:
The usage of .ngrok.io vs .ngrok.app interchanged within the application can lead to confusion for the user on which URL to use.
source: was confused