Unable to join Zoom Webinar with Server-to-Server App and web SDK

I created an Server-to-Server app to create Webinars which is working correctly.
But when the users join it from our frontend page using Web SDk CDN, it doesnt join. The ‘ZoomMtg.init’ call is successful, we attempt to call ‘ZoomMtg.join’. Neither the success nor the error callbacks that we provided are executed. This leads to the users being stuck on the “Joining Meeting…” screen.

Here is the compiled code:

    ZoomMtg.setZoomJSLib('https://source.zoom.us/3.6.0/lib', '/av');
    ZoomMtg.preLoadWasm();
    ZoomMtg.prepareWebSDK();

    var meeting_id = "81735283950";
    var leave_url = "https://domain.tld/close_webinar/:status/:meeting_id";
    leave_url = leave_url.replace(':status', 'recorded');
    leave_url = leave_url.replace(':meeting_id', meeting_id);


    ZoomMtg.init({
        leaveUrl: leave_url,
        isSupportAV: true,
        meetingInfo: ['participant'],
        success: (success) => {
            console.log('success',success);
            ZoomMtg.join({
                signature: "RlduSDI3QUhRWldyV3k4MUtlWWRhdy44MTczNTI4Mzk1MC4xNzIwNTU2NjYwNzc1LjEuL0VUTWpMYlYrVGM0NTJ3QVBDYVFtUXAxMXZySXBuencrQldFYU5nN0l4dz0",
                meetingNumber: "81735283950",
                userName: "System Administrator",
                appKey: "FWnH27AHQZWrWy81KeYdaw",
                sdkKey: "FWnH27AHQZWrWy81KeYdaw",
                userEmail: "abc@gmail.com",
                passWord: "",
                success: (success) => {
                    console.log('success1',success);

                    const URL = window.location.origin;
                    const SOCKET_PORT = "4007";
                    const SOCKET_IO = URL + ":" + SOCKET_PORT;
                    const socket = io.connect(SOCKET_IO, {transports: ['websocket', 'polling', 'flashsocket']});
                    socket.on('connect', function() {
                        console.log('socket.connected', socket.connected);
                    });
                    socket.emit('webinar_started', {webinar_id: "28"});

                    $.get('https://domain.tld/webinar/update_start_status/81735283950', function (data) {});
                    ZoomMtg.getAttendeeslist({});
                },
                error: (error) => {
                    console.log(error)
                }
            })
        },
        error: (error) => {
            console.log(error)
        },
    });




$(document).on('clic', '.leave-meeting-options__btn--danger', function (event) {
    event.preventDefault();
})