Add conference to event Google Calendar API

I can create an event but I can't create an event with a conference.

I tried all these types: "eventHangout" "eventNamedHangout" "hangoutsMeet" but still getting Invalid conference type value

Google.GoogleApiException: 'Google.Apis.Requests.RequestError
Invalid conference type value. [400]
Errors [
  Message[Invalid conference type value.] Location[ - ] Reason[invalid] Domain[global]
]

Here's the code that creates and executes an event:

CalendarService service = GetCalendarService();

EventDateTime start = new EventDateTime();
start.DateTime = new DateTime(2021, 02, 19, 18, 47, 0);

EventDateTime end = new EventDateTime();
end.DateTime = new DateTime(2021, 02, 19, 18, 50, 0);

Event newEvent = new Event();
newEvent.Start = start;
newEvent.End = end;
newEvent.Summary = "New event";
newEvent.Description = "description";

newEvent.ConferenceData = CreateConferenceData();

EventsResource.InsertRequest request = service.Events.Insert(newEvent, calendarId);
request.ConferenceDataVersion = 1;
Event createdEvent = request.Execute();

Here's the code of CreateConferenceData() method:

 ConferenceData conferenceData = new ConferenceData()
 {
     CreateRequest = new CreateConferenceRequest()
     {
          RequestId = Guid.NewGuid().ToString(),
          ConferenceSolutionKey = new ConferenceSolutionKey()
          {
             Type = "hangoutsMeet" // Change according to your preferences
          };
     }
 };

 return conferenceData;