How to send oAuth code from Visualforce page to LWC Components Which are on 2 different Windows Using Post Messages?

I’m new to salesforcce developement tried integrating two salesforce org’s using oAuth Webserver flow i’m getting the callback code to a vf page but when i’m sending the code using post messages to Lwc it’s throwing following error

Can any one suggest a way to do oAuth Web server flow using Lwc

Failed to execute 'postMessage' on 'DOMWindow': The target origin provided ('https://bnthinc-8d-dev-ed.develop.lightning.force.com') does not match the recipient window's origin ('https://bnthinc-8d-dev-ed--testingbnth.develop.vf.force.com').

Code in vf Page to Post Message

<apex:page >

  <script>
    //window.top.postMessage(window.location.hash.substring(1),'https://bnthinc-8d-dev-ed.develop.lightning.force.com');
     parent.postMessage('Code','https://bnthinc-8d-dev-ed.develop.lightning.force.com');
  </script>

</apex:page>

Code in LWC to Catch Message

 doAuth(){

        let oAuthUrl=`${BASE_URL}?client_id=${client_Id}&redirect_uri=${redirected_Uri}&response_type=code`;
        window.open(oAuthUrl);

        window.onmessage((msg)=>{
            console.log('Data>>',msg.data);
            console.log('Message>>',msg);
        })
    }

I’m new to salesforcce developement tried integrating two salesforce org’s using oAuth Webserver flow i’m getting the callback code to a vf page but when i’m sending the code using post messages to Lwc it’s throwing following error

Can any one suggest a way to do oAuth Web server flow using Lwc

Failed to execute 'postMessage' on 'DOMWindow': The target origin provided ('https://bnthinc-8d-dev-ed.develop.lightning.force.com') does not match the recipient window's origin ('https://bnthinc-8d-dev-ed--testingbnth.develop.vf.force.com').