Trouble in facebook messenger account linking process - facebook

Question

Problem:
In my case what happening is, it is always saying Account Linking Failed
What I am doing
following this doc word by word: https://developers.facebook.com/docs/messenger-platform/identity/account-linking/
when I need user to be linked to my app, I send a login button to the user like this:
http.post(`https://graph.facebook.com/v2.6/me/messages?access_token=${PAGE_ACCESS_TOKEN}`, {
"recipient": {
"id": "2829343507138856"
},
"message": {
"attachment": {
"type": "template",
"payload": {
"template_type": "button",
"text": "Try the log in button!",
"buttons": [
{
"type": "account_link",
"url": "https://dev-sysborg.auth0.com/authorize?response_type=code&client_id=VYierFrTxMb1Kky3DfPEqUHXaShdmH43"
}
]
}
}
}
}).then(() => {
response.send("ok")
})
user see this login button like this on their messenger screen:
when user try to login by pressing the button, it pops up a new window and open login screen in that window:
and after entering credentials it redirects to a screen which says Account linking failed,
something like this:
I am sure there is nothing wrong with the Auth0 configuration because it is working fine with postman and connected very well with some other platforms
someone said I must have to subscribe to account linking event so I have subscribed to these three events: messages, messaging_postbacks, messaging_account_linking
I am Stuck at the end of the story,
Please help me out