how to resolve ( [error] => invalid_client [error_description] => client authentication failed ) for ebay

Question

public function authorizationToken(){
$link = "https://api.ebay.com/identity/v1/oauth2/token";
$codeAuth = base64_encode($this->clientID.':'.$this->certID);
$ch = curl_init($link);
curl_setopt($ch, CURLOPT_HTTPHEADER, array('Content-Type: application/x-www-form-urlencoded','Authorization: Basic '.$codeAuth));
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, false);
curl_setopt($ch, CURLOPT_POST, 1);
curl_setopt($ch, CURLOPT_POSTFIELDS, "grant_type=authorization_code&code=".urlencode($this->authCode)."&redirect_uri=".$this->ruName."&scope=".urlencode('https://api.ebay.com/oauth/api_scope'));
$response = curl_exec($ch);
$json = json_decode($response, true);$info = curl_getinfo($ch);
curl_close($ch);print_r($json);}

Answer 1

It looks like you are getting refresh_token confused with authorization_token, because you are mixing incompatible parameters between the two different requests.

If you are trying to get the initial "AccessToken" (AKA UserAccessToken, access_token, AuthToken, ...), then you should not include the scope parameter in your request body. So your request body should look like this:

grant_type=authorization_code&redirect_uri=<redirect_uri>&code=<authorization_code>

Where <authorization_code> is the value that is returned from here.

For an overview of the difference, I'd recommend this answer over the official docs on the topic.

Answer 2

Try this code

  public function authorizationToken(){
    $link = "https://api.ebay.com/identity/v1/oauth2/token";
    $codeAuth = base64_encode($this->clientID.':'.$this->certID);
    $ch = curl_init($link);
    curl_setopt($ch, CURLOPT_HTTPHEADER, array('Content-Type: application/x-www-form-urlencoded','Authorization: Basic '.$codeAuth));
    curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
    curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, false);
    curl_setopt($ch, CURLOPT_POST, 1);
    curl_setopt($ch, CURLOPT_POSTFIELDS, "grant_type=client_credentials&scope=".urlencode('https://api.ebay.com/oauth/api_scope'));
    $response = curl_exec($ch);
    $json = json_decode($response, true);
    $info = curl_getinfo($ch);
    curl_close($ch);
    print_r($json);
}