PKCE Token Refresh leads to 400 Invalid Request

[deeema]

I'm implementing PKCE auth flow. If the token expires, I try to refresh the token.

I send a POST-request to the "https://accounts.spotify.com/api/token" Endpoint with:

Payload:
{
"refresh_token": "[my refresh token]",
"grant_type": "refresh_token",
"client_id": "[my client id]"
}

Headers:

{
"Content-Type": "application/x-www-form-urlencoded"
}

I get a 400 "invalid_request" without any further explanation.

Response:
{
"error": "invalid_request",
"error_description": "",
}

I assume theres something wrong with the request but I checked everything 5 times over, it should be exactly like in the docs. What am I missing here?

[russnelson]

I am seeing the same issue. Did you ever resolve it?