Google Calendar API marking new events as "cancelled" - php

Question

I am trying to create events in my calendar via the calendar API.
Below is the object I am pushing to the API:
Google_Event Object
(
[__creatorType:protected] => Google_EventCreator
[__creatorDataType:protected] =>
[creator] => Google_EventCreator Object
(
[self] => 1
[displayName] =>
[email] => gcalevent#golden-hook-134443.iam.gserviceaccount.com
[id] =>
)
[__organizerType:protected] => Google_EventOrganizer
[__organizerDataType:protected] =>
[organizer] => Google_EventOrganizer Object
(
[self] => 1
[displayName] =>
[email] => gcalevent#golden-hook-134443.iam.gserviceaccount.com
[id] =>
)
[summary] => Hair: Elliot Test
[id] => 421a880v7dqb97p5voqsp198ac
[__attendeesType:protected] => Google_EventAttendee
[__attendeesDataType:protected] => array
[attendees] => Array
(
[0] => Google_EventAttendee Object
(
[comment] =>
[displayName] => Elliot Test
[responseStatus] => accepted
[self] =>
[id] =>
[additionalGuests] =>
[resource] =>
[organizer] =>
[optional] =>
[email] => hello#elliot.co.uk
)
)
[htmlLink] => https://www.google.com/calendar/event?eid=NDIxYTg4MHY3ZHFiOTdwNXZvcXNwMTk4YWMgZ2NhbGV2ZW50QGdvbGRlbi1ob29rLTE2NDQyMS5pYW0uZ3NlcnZpY2VhY2NvdW50LmNvbQ
[recurrence] =>
[__startType:protected] => Google_EventDateTime
[__startDataType:protected] =>
[start] => Google_EventDateTime Object
(
[date] =>
[timeZone] =>
[dateTime] => 2019-09-10T15:00:00Z
)
[etag] => "3136239546092000"
[location] =>
[recurringEventId] =>
[__gadgetType:protected] => Google_EventGadget
[__gadgetDataType:protected] =>
[gadget] =>
[status] => confirmed
[updated] => 2019-09-10T12:49:33.046Z
[description] => Price: £10.00
Services: Testing
[iCalUID] => 421a880v7dqb97p5voqsp198ac#google.com
[__extendedPropertiesType:protected] => Google_EventExtendedProperties
[__extendedPropertiesDataType:protected] =>
[extendedProperties] =>
[endTimeUnspecified] =>
[sequence] => 0
[visibility] =>
[guestsCanModify] =>
[__endType:protected] => Google_EventDateTime
[__endDataType:protected] =>
[end] => Google_EventDateTime Object
(
[date] =>
[timeZone] =>
[dateTime] => 2019-09-10T16:00:00Z
)
[attendeesOmitted] =>
[kind] => calendar#event
[locked] =>
[created] => 2019-09-10T12:49:33.000Z
[colorId] =>
[anyoneCanAddSelf] =>
[__remindersType:protected] => Google_EventReminders
[__remindersDataType:protected] =>
[reminders] => Google_EventReminders Object
(
[__overridesType:protected] => Google_EventReminder
[__overridesDataType:protected] => array
[overrides] =>
[useDefault] => 1
)
[guestsCanSeeOtherGuests] =>
[__originalStartTimeType:protected] => Google_EventDateTime
[__originalStartTimeDataType:protected] =>
[originalStartTime] =>
[guestsCanInviteOthers] =>
[transparency] =>
[privateCopy] =>
)
Which appears to be work fine, however when I go to retrieve that event using the ID: 421a880v7dqb97p5voqsp198ac it shows all the above details but the status is marked as "cancelled" and therefore it isn't showing in my calendar:
{
"kind": "calendar#event",
"etag": "\"3136239559346000\"",
"id": "421a880v7dqb97p5voqsp198ac",
"status": "cancelled",
"htmlLink": "https://www.google.com/calendar/event?eid=NDIxYTg4MHY3ZHFiOTdwNXZvcXNwMTk4YWMgaGVsbG9AZWxsaW90cmVldmUuY28udWs",
"created": "2019-09-10T12:49:33.000Z",
"updated": "2019-09-10T12:49:39.673Z",
"summary": "Hair: Elliot Test",
"description": "Price: £10.00\nSerivices: Testing",
"creator": {
"email": "gcalevent#golden-hook-134443.iam.gserviceaccount.com"
},
"organizer": {
"email": "gcalevent#golden-hook-134443.iam.gserviceaccount.com"
},
"start": {
"dateTime": "2019-09-10T16:00:00+01:00"
},
"end": {
"dateTime": "2019-09-10T17:00:00+01:00"
},
"iCalUID": "421a880v7dqb97p5voqsp198ac#google.com",
"sequence": 0,
"attendees": [
{
"email": "hello#elliot.co.uk",
"displayName": "Elliot Test",
"self": true,
"responseStatus": "accepted"
}
],
"reminders": {
"useDefault": true
}
}
This has previously been working fine for months and is now no longer working without any changes from my side.
Can anyone provide any insight into why this might be happening?
Thanks