Php get email and username

API
2 
 curl_setopt ($ch, CURLOPT_HTTPHEADER, array (
     'Authorization: Bearer'. $validate_token,
     'Client-ID:'. $clientID
 ));

should be

 curl_setopt ($ch, CURLOPT_HTTPHEADER, array (
     'Authorization: Bearer '. $validate_token,
     'Client-ID:'. $clientID
 ));

You were missing the space after Bearer and before the token