Why is there no sound after answering a call (Windows, Freeswitch, SIP.JS)?

Question

FreeSWITCH

Windows. Server Freeswitch (IP public).
Set up "Click to Call" on the site using SIPJS (wss-binding).
Subscriber "A" on the site presses the button and a call is formed to Subscriber "B".
"B" answers and no one hears anyone (Neither "A" nor "B"). The recording of the conversation captures both subscribers (which means the data passes).
What is the problem then? On the browser or on the server?