Immediate help on Google Calendat API BULK operations

I NEED IMMEDIATE HELP TO HAVE A PHO SCRIPT CORRECTLY RUNNING I'm using the PHP library to publish and delete events to a Google calendar via Google API. Everything it is ok when I add or delete a single event. My problem is if I try to use BATCH operations since I have to add/remove a lot of events. In case of batch operation, I get response (401) Login Required, but the $client it is the same that is perfectly working with single operations. This creates the client and service $client2 = new Google_Client(); $client2->setClientId($client_id); $client2->setClientSecret($client_secret); $client2->setRedirectUri($redirect_uri); $client2->setDeveloperKey($oauth2['authToken']); $service2 = new Google_Service_Calendar($client2) This for adding single event: $created = $service->events->import($oauth2['gcalid'], $gevent, $optParams = array()); This for deleting single event: $service->events->delete($oauth2['gcalid'], $item->getId()); This is the code for BULK operations that are not working. $client2->setUseBatch(true); $batch2 = new Google_Http_Batch($client2); foreach ($items as $item){ echo "Elimino evento " . $item->getId() . "\n"; $req1 = $service2->events->delete($oauth2['gcalid'], $item->getId()); $batch2->add($req1); } $results2 = $batch2->execute(); $client->setUseBatch(false); How could I solve? Thank you, Michele