In LWC Visualforce iframe not showing in experience site

Question

I have assigned visualforce and apex class on guest user profile.Also i enabled Available for Lightning Experience, Experience Builder sites, and the mobile app. But still in experience its showing an error refused to connect wise-impala-bk33p6-dev-ed.trailblaze.my.site.com refused to connect.

Error on experience site

Enabled Vf page for guest user profile

on Vf Page

 paymentElement.js
 if (this.siteclientSecret == undefined){
        this.siteclientSecret = '/apex/PaymentElements?clientSecret=' + result.client_secret;
        console.log(this.siteclientSecret);
    } 
//i tried like below as well its showing invalid page
if (this.siteclientSecret == undefined){
            this.siteclientSecret = 'myCommunity/apex/PaymentElements?clientSecret=' + result.client_secret;
            console.log(this.siteclientSecret);
        } 

//hardcoded the site page but still getting the same error
if (this.siteclientSecret == undefined){
            this.siteclientSecret = 'https://wise-impala-bk33p6-dev-ed.trailblaze.my.site.com/myCommunity/apex/PaymentElements?clientSecret=' + result.client_secret;
            console.log(this.siteclientSecret);
        } 


paymentlement.html
<div class="slds-box slds-theme--default">
        <iframe allowpaymentrequest id="add_payment" src={siteclientSecret} height="600px" width="100%"></iframe>
    </div>

Answer 1

You need to allow access to the domain first, as stated in Put Visualforce Pages on External Domains.

From Setup, in the Quick Find box, search for Session Settings, and then click Session Settings. Under Clickjack Protection, select Enable clickjack protection for customer Visualforce pages with headers disabled and Enable clickjack protection for customer Visualforce pages with standard headers.

Then under Trusted Domains for Inline Frames, add the trusted external domains where you allow framing and set the iframe type to Visualforce Pages. Ensure that your domain names meet format requirements. You can add up to 512 external domains.