Microsoft Graph findMeetingTimes endpoint not working - microsoft-graph-api

Question

Please do not report as duplicate because all other topics have not solved my issue, thanks.
I'm using Microsoft Graph api to list and create calendar events, however I can't seem to make the findMeetingTimes endpoint work.
This is my authorization URL:
https://login.microsoftonline.com/consumers/oauth2/v2.0/authorize?client_id=xxxxx&response_type=code&redirect_uri=xxxxx&response_mode=form_post&scope=openid%20profile%20User.ReadWrite%20User.ReadBasic.All%20Sites.ReadWrite.All%20Contacts.ReadWrite%20People.Read%20Notes.ReadWrite.All%20Tasks.ReadWrite%20Mail.ReadWrite%20Files.ReadWrite.All%20Calendars.ReadWrite&state=12345
Then I request an access token using the same scopes:
$request = json_decode($guzzle->post('https://login.microsoftonline.com/common/oauth2/v2.0/token', [
'headers' => [
'Content-Type' => 'application/x-www-form-urlencoded'
],
'form_params' => [
'client_id' => 'xxxxx',
'scope' => 'openid profile User.ReadWrite User.ReadBasic.All Sites.ReadWrite.All Contacts.ReadWrite People.Read Notes.ReadWrite.All Tasks.ReadWrite Mail.ReadWrite Files.ReadWrite.All Calendars.ReadWrite',
'code' => $auth_code,
'grant_type' => 'authorization_code',
'redirect_uri' => 'xxxxx',
'client_secret' => 'xxxxx'
],
])->getBody()->getContents());
After that I'm trying the findMeetingTimes endpoint using:
$request = json_decode($guzzle->post('https://graph.microsoft.com/v1.0/me/findMeetingTimes', [
'headers' => [
'Authorization' => 'Bearer ' . $accessToken,
'Content-Type' => 'application/json',
],
'body' => '{
"attendees": [
{
"type": "required",
"emailAddress": {
"name": "My Name",
"address": "myemail#hotmail.com"
}
}
],
"timeConstraint": {
"activityDomain":"work",
"timeslots": [
{
"start": {
"dateTime": "2019-04-02T09:00:00",
"timeZone": "Pacific Standard Time"
},
"end": {
"dateTime": "2019-04-03T17:00:00",
"timeZone": "Pacific Standard Time"
}
}
]
}
}',
])->getBody()->getContents());
However, it keeps returning:
401 - Unauthorized: Access is denied due to invalid credentials.
You do not have permission to view this directory or page using the credentials that you supplied.
Who's going to be my hero? :/

Answer 1

This is by design. From the documentation:
Note The findMeetingTimes action is currently available to Office 365 work or school mailboxes, but not personal, outlook.com mailboxes.