google analytics invalid credentials for a specific account - php

Question

Hi i am using a different account for google analytics and is returning an error:
GDataauthErrorAuthorizationInvalid Credentials
Though for my previous account is working fine. it could be because i missed some things in the registration process, could anyone give me a detailed steps for the registration to work for oauth 2.0 using api_key for google analytics v2.4
thank you
//returns session token for multiple calls to API
function get_session_token($onetimetoken) {
$output = call_api($onetimetoken, "https://www.google.com/accounts/AuthSubSessionToken");
if(preg_match("/Token=(.*)/", $output, $matches)) {
$sessionToken = $matches[1];
} else {
echo "Error authenticating with Google.";
exit;
}
return $sessionToken;
}
//gets the data
function call_api($sessionToken,$url){
$curl = curl_init($url);
curl_setopt($curl, CURLOPT_RETURNTRANSFER, 1);
if ($_SESSION['authSub']==true){
$curlheader[0] = sprintf("Authorization: AuthSub token=\"%s\"/n", $sessionToken);
} else {
$curlheader[0] = "Authorization: GoogleLogin auth=" . $sessionToken;
}
curl_setopt($curl, CURLOPT_HTTPHEADER, $curlheader);
$response = curl_exec($curl);
curl_close($curl);
return $response;
}
$requrlvisits = sprintf("https://www.googleapis.com/analytics/v2.4/data?ids=ga:%s&dimensions=ga:date&metrics=ga:visits,ga:pageviews,ga:bounces,ga:timeOnSite&start-date=%s&end-date=%s&sort=ga:date&key=%s",$get_profid[9],$date1,$date2,$api_key);
// echo $requrlvisits;
$visitsxml = call_api($_SESSION['sessionToken'],$requrlvisits);
$visits = parse_data($visitsxml);
print_r($visitsxml);