Is it possible to invite users outside of the domain? - calendar

Question

I am building a web app where, basically, one user can pay to meet another user in a Google Meet. This would then create a Google Meet Calendar Event where the two users + one user from the company would be invited to a video meeting.
Basically, domain is example.com. This email address (service account), must invite attendee1#companyX.com and attendee2#companyY.com. When I put the event with no attendee, no problemo. As soon as I put the other attendees, I get:
{ "error": { "errors": [ { "domain": "calendar", "reason": "forbiddenForServiceAccounts", "message": "Service accounts cannot invite attendees without Domain-Wide Delegation of Authority." } ], "code": 403, "message": "Service accounts cannot invite attendees without Domain-Wide Delegation of Authority." } }
I want to use a service account since it's the company (example.com), it never changes and I don't want the website to break if the password/whatever changes.
Here is my code:
$client = new Google\Client();
$client->useApplicationDefaultCredentials();
$client->addScope(Google_Service_Calendar::CALENDAR);
$service = new Google_Service_Calendar($client);
$event = new Google_Service_Calendar_Event(array(
'summary' => 'Entretien vidéo',
'start' => array(
'dateTime' => '2015-05-28T09:00:00-07:00',
'timeZone' => 'America/Los_Angeles',
),
'end' => array(
'dateTime' => '2015-05-28T17:00:00-07:00',
'timeZone' => 'America/Los_Angeles',
),
'recurrence' => array(
'RRULE:FREQ=DAILY;COUNT=2'
),
'attendees' => [
[
'email' => "attendee#email.com"
]
],
"conferenceData"=> [
"createRequest" => [
"conferenceSolutionKey"=> [
"type"=> "hangoutsMeet"
],
"requestId"=> "7qxalsvy0exxaje"
]
],
));
$calendarId = 'primary';
$event = $service->events->insert($calendarId, $event);
printf('Event created: %s\n', $event->htmlLink); });
Can anybody help me about this?
Thanks!

Answer 1

To use the Google Calendar with your domain you need sign up for Gsuite
see https://support.google.com/a/answer/39410?hl=en
Prices plans: https://support.google.com/a/answer/1247360?hl=en