Authentication Error - Value cannot be null. (Parameter 'value') about aspnet-snippets-sample

[jasonjoh]

Thanks for reporting. This sample does need an update as the authentication libraries have been significantly re-worked since this was last touched. However it should still work.

Can you check something for me? Can you go to Graph Explorer, login with the same account you're using to reproduce this, and run a GET https://graph.microsoft.com/v1.0/me/mailboxsettings? If that works, do you see a value for timeZone? You may see it inside workingHours or automaticRepliesSetting, but specifically I'm looking to see if it's set at the top level (like the third line below).

{
    "@odata.context": "https://graph.microsoft.com/v1.0/$metadata#users('xxx')/mailboxSettings(timeZone)",
    "archiveFolder": "AAMkAGVl...AAA=",
    "timeZone": "Eastern Standard Time",
    "delegateMeetingMessageDeliveryOptions": "sendToDelegateAndPrincipal",
    "dateFormat": "",
    "timeFormat": "",
    "automaticRepliesSetting": {
        "status": "disabled",
        "externalAudience": "none",
        "internalReplyMessage": "",
        "externalReplyMessage": "",
        "scheduledStartDateTime": {
            "dateTime": "2021-02-25T20:00:00.0000000",
            "timeZone": "UTC"
        },
        "scheduledEndDateTime": {
            "dateTime": "2021-02-26T20:00:00.0000000",
            "timeZone": "UTC"
        }
    },
    "language": {
        "locale": "en-US",
        "displayName": "English (United States)"
    },
    "workingHours": {
        "daysOfWeek": [
            "monday",
            "tuesday",
            "wednesday",
            "thursday",
            "friday"
        ],
        "startTime": "09:00:00.0000000",
        "endTime": "17:00:00.0000000",
        "timeZone": {
            "name": "Eastern Standard Time"
        }
    }
}

[andrewbaker-uk]

Ahh this is slightly embarrassing. I'm using a Office 365 Developer account and I hadn't yet accessed the mailbox.

I didn't have an value for timeZone on the top level like in the example. As soon as I went to the mailbox and tried again, the value was populated :)

Thanks for the help

[jasonjoh]

Thanks for confirming! I suspected this was the case as someone else had a similar issue with the tutorial that this is based off of. The fix hasn't come over to this repo yet :D.