PHP Google Search Console API "invalid_grant" response - google-api

Question

I am using following PHP code to fetch data through Google Search Consonle API.
It was working fine 2 months ago but now it's showing invalid grand message instead of data. Please! need your help.
error: '400 - {"error":"invalid_grant","error_description":"Bad Request"}'
I've right credentials included. Also you can see token is saved in file and is being fetched on demand and getting refresh too. I don't why it's stopped working.
Thanks
At the top I've added
use Google_Client;
use Google_Service_Webmasters_SearchAnalyticsQueryRequest;
use Google_Service_Webmasters;
and here is the code
$siteToFetch = (!empty($site)) ? base64_decode($site) : "https://www.siteiamfulluserof.com/";
$client_id = 'XXXXXXXXXXXX-FULL-TOKEN-REMOVED';
$client_secret = 'xxxxxx-xxxxx_xxxxxxxxxxxxxxx-xxxx';
$redirect_uri = 'http://localhost/redirect_url';
$client = new Google_Client();
$client->setClientId($client_id);
$client->setClientSecret($client_secret);
$client->setRedirectUri($redirect_uri);
$client->setAuthConfig(public_path("client_secret_latest.json"));
$client->setScopes("https://www.googleapis.com/auth/webmasters", 'https://www.googleapis.com/auth/webmasters.readonly');
if (file_exists($this->tokenFile)) {
$accessToken = json_decode(file_get_contents($this->tokenFile), true);
} else {
// Request authorization from the user.
$authUrl = $client->createAuthUrl();
header('Location: ' . filter_var($authUrl, FILTER_SANITIZE_URL));
if (isset($_REQUEST['code'])) {
$authCode = $_REQUEST['code'];
// Exchange authorization code for an access token.
$accessToken = $client->fetchAccessTokenWithAuthCode($authCode);
header('Location: ' . filter_var($redirect_uri, FILTER_SANITIZE_URL));
if (!file_exists(dirname($this->tokenFile))) {
mkdir(dirname($this->tokenFile), 0700, true);
}
file_put_contents($this->tokenFile, json_encode($accessToken));
} else {
exit('No code found');
}
}
$client->setAccessToken($accessToken);
// Refresh Token if expired.
if ($client->isAccessTokenExpired()) {
$refreshTokenSaved = $client->getRefreshToken();
$client->fetchAccessTokenWithRefreshToken($refreshTokenSaved);
}
if ($client->getAccessToken()) {
$googleQuery = new \Google_Service_Webmasters_SearchAnalyticsQueryRequest();
$googleQuery->setStartDate(date('Y-m-d', strtotime('-180 days')));
$googleQuery->setEndDate(date('Y-m-d', strtotime('-3 days')));
$googleQuery->setDimensions(['page', 'date']);
$googleQuery->setSearchType('web');
try {
$service = new Google_Service_Webmasters($client);
$response = $service->searchanalytics->query($sitesFetched[0]["site"], $googleQuery);
$siteData = [];
foreach ($response as $row) {
$siteData[] = [
"site" => $row->keys[0],
"date" => $row->keys[1],
"clicks" => $row->clicks,
"impressions" => $row->impressions,
"ctr" => $row->ctr,
"position" => $row->position,
];
}
} catch (\Exception $e) {
$error = json_decode($e->getMessage());
if ($error->error = "invalid_grant") {
echo "You don't have proper permissions to access this site or data is being fetched.";
}
}
}