Follow the salesforce doc to send data to SalesForce,

window.addEventListener("onEmbeddedMessagingReady", () => {
    console.log("Received the onEmbeddedMessagingReady event…");

    // Send data to Salesforce
    var browserInfo = getBrowserInfo();
    embeddedservice_bootstrap.prechatAPI.setHiddenPrechatFields({"Web_Page": document.title});
    embeddedservice_bootstrap.prechatAPI.setHiddenPrechatFields({"Web_Page_URL": window.location.href});
    embeddedservice_bootstrap.prechatAPI.setHiddenPrechatFields({"Previous_Web_Page_URL": document.referrer});
    embeddedservice_bootstrap.prechatAPI.setHiddenPrechatFields({"City" : city});
    embeddedservice_bootstrap.prechatAPI.setHiddenPrechatFields({"Country" : country});
    embeddedservice_bootstrap.prechatAPI.setHiddenPrechatFields({"IP_Address" : userIp});
    embeddedservice_bootstrap.prechatAPI.setHiddenPrechatFields({"Operation_System" : browserInfo.Operation_System});
    embeddedservice_bootstrap.prechatAPI.setHiddenPrechatFields({"Device" : browserInfo.Device});
    embeddedservice_bootstrap.prechatAPI.setHiddenPrechatFields({"Browser" : browserInfo.Browser});
});

embeddedservice_bootstrap.init(…)

Only a few of my sites cannot reveive data while Most of the other sites are receiving data just fine. Im sure the bug sites use the same code and environment as the fine sites.

expected:
enter image description here
actual:
enter image description here

Check salesforce dev doc and check api on page console cannot find any hint enter image description here