400 Bad Request - Access Token - PKCE Auth Code Flow

[dm17]

Hello,
I'm currently on Step 2 (Requesting Access Token) of the Auth Code Flow using PKCE, but I am unable to retrieve the access token.
Problem
I am receiving a 400 Bad Request when sending my POST request to the https://accounts.spotify.com/api/token endpoint.
Code Snippet
Code

Everything seems correct when I output to the console, but it seems like I'm missing something.
Please help

Edit:

To make it easier to check my work I will reference the Auth Code Flow documentation here and where that can be found in my code (above).

• Making a POST request to the /api/token endpoint:
  - options.method = "POST"
  - SPOTIFY_TOKEN_ENDPOINT = "https://accounts.spotify.com/api/token"
• Request body should contain the parameters in application/x-www-form-urlencoded:
  - headers["Content-Type"] = "application/x-www-form-urlencoded"
  - bodyObject = parameters needed
    searchParams = URLSearchParams object containing parameters and values
    requestBody = bodyObject in x-www-form-urlencoded form
  - request.write(requestBody) = request sending parameters in the body in x-www-form-urlencoded form
• Request body parameters needed (found in bodyObject):
  - grant_type = "authorization_code"
  - code = codeVal, the code value found in the URL when redirected after Authorization
  - redirect_uri = redirectURI, the same URI sent in Step 1 of Auth Code Flow
  - client_id = environment variable that is expanded at runtime using dotenv library
  - code_verifier = codeVerifier, the code verifier my website created and sent in Step 1 of Auth Code Flow (have confirmed these match)
• HTTP Headers:
  - headers.Authorization = base64 encoded(<client_id environment variable>:<client_secret environment variable>)
  - headers["Content-Type"] = "application/x-www-form-urlencoded"

[mikemgg123]

same issue. did you figure it out?

[deeema]

I have the same problem when trying to refresh my token.
I'm sending a POST-request to endpoint "https://accounts.spotify.com/api/token" and getting 400 "Invalid request". No error message. I just don't get what the problem is.

Payload:
{
"refresh_token": [my refresh token],
"grant_type": "refresh_token",
"client_id": "[my client id]"
}
Headers.
{
"Content-Type": "application/x-www-form-urlencoded"
}