You can also opt to setup your own TURN & STUN Server. First you have to get a Server to setup your TURN Server.
Read this for minimum server specification required for TURN & STUN Server:
Coturn is a free and open-source implementation of a TURN and STUN server for VoIP and WebRTC. It is available at https://github.com/coturn/coturn.
Here are reference articles on how to setup TURN Server with Coturn:
Once installed you get TURN/STUN server url and credentials, you can go to Configuration -> ICE Servers configuration and put the required details.
Or you can hire us to setup STUN/TURN Server for you. We charge $100 for one time setup of TURN Server.