User who has authorized TLS certificate only able to connect to Open-sip server from application (Android and iOS).
What we need to change in config file for only TLS connection to Open-sip server.
Can you try uncommenting the line of startTLS from config file and make it true as a value?
It should work!
Also make sure that your Android and iOS clients are configured to accept TLS connections(though most of the time it's default behaviour).