ESI SSO POST error Invalid Grant

[Kurtisthe1st]

When attempting to authenticate following the steps listed in Web_based_sso_flow I receive
error: “invalid grant”
error_description: “Grant type authorization_code is not supported.”

The applicable code in my JS (React) application is

const authID = encode(props.secrets.client_id+":"+props.secrets.secret_key);
    
    const bodyValues = {
        'grant_type': 'authorization_code',
        'code': code
    }
    
    const formBody = Object.keys(bodyValues).map(key => encodeURIComponent(key) + '=' + encodeURIComponent(bodyValues[key])).join('&');
    
    const requestOptions = {
        method: 'POST',
        headers: {'Authorization': 'Basic ' + authID,
            'Content-Type': 'application/x-www-form-urlencoded',
            'Host': 'login.eveonline.com'},
        body: formBody
    }
    
    console.log("Sending authorization request", requestOptions);
    fetch('https://login.eveonline.com/v2/oauth/token', requestOptions)

I am stumped as to how I am formatting this request incorrectly as the documentation clearly states that authorization_code is the correct grant type.

An example of the body edited to remove the actual code

grant_type=authorization_code&code=<code>

I am aware that i need to switch over to native_sso_flow but wanted to get a working post request first.

Edit: I receive the error description "“Grant type is not supported.” with postman

[Steve_Ronuken]

The web based flow does not work with V2.

[Dimonian]

Face the same issue. How to fix it? What does it mean V2 is not supported web? How then the users can log in from a website?

[Dimonian]

I found a way how to solve this. For some reason it’s start to work if add client_Id, and scope inside request body (const bodyValues = ). Also 'Authorization': 'Basic ' + authID, sould be removed form header because system will read credential from request body.

[Laguna_Elon_Rothschild]

This did not work for me, and I’m getting the same error.