Unable to parse interaction_code from the url

[mbudeci]

Hello, please help me understand this error.
I am trying to add Okta Sign-In Widget to our website, after I pass the authentication step I get a callback on http://localhost:3000/login/callback with this error.

{
"status": 500,
"errorText": "Unable to parse interaction_code from the url",
"env": "dev"
}

if I delete useClassicEngine another error appears,

const widgetConfig = {
      useInteractionCodeFlow: true,
      useClassicEngine: true,
      issuer,
      clientId,
      redirectUri,
      state,
      scopes,
      codeChallenge,
      codeChallengeMethod,
      otp,
};

[akash-okta]

Hi there,

Please note that Interaction Code Flow was introduced in Okta Identity Engine. So, when you keep the useClassicEngine property to ‘true’, the Sign-in widget will use the Classic Engine and will produce this error.

To get rid of this error, you will require to set the useInteractionCodeFlow property to ‘false’ if you do not have the requirement of the Interaction Code Flow. Otherwise, you will require to upgrade your Okta Classic org to Okta Identity Engine - Identity Engine upgrade overview | Okta Developer

You can learn more here in this article - Okta Help Center (Lightning)

You can refer to this documentation to choose the right flow based on your requirement - OAuth 2.0 and OpenID Connect overview | Okta Developer