Error Sending an Event Invite: Invitee is in inviter tenant RRS feed

  • Question

  • User1314407993 posted

    I'm getting the error in this post's title. The only suggestion I found that addressed this directly stated this:

    1. You're attempting to invite someone with an address from one of the verified domains. In other words, if your tenant lists company.onmicrosoft.com and company.com as verified domains, attempting to invite an address ending in @company.onmicrosoft.com or @company.com will fail.

    2. The external email address you supplied already exists in the tenant (typically because they've already accepted a previous invitation).

    Both of these boil down to the same root cause: you cannot send an invitation to an email address that has already been assigned to an existing user.

    I don't understand this. What does it mean for someone to already exist in the tenant? Just accepting an invite to the event? That's my assumption, but I have no idea what it means to send an invite to an email address assigned to an existing user. Does that mean essentially the same thing as #1? I thought that meant since my user account was the one used to set up an event, I couldn't invite myself to the same event, but I sent an invite to someone else, and got the exact same error.  This is the code I'm using: 

    public async Task<Invitation> SendInvitation(string invitee, string redirectUrl)
        var graphClient = GetAuthenticatedClient();
        var invitation = new Invitation
            InvitedUserEmailAddress = invitee,
            InviteRedirectUrl = redirectUrl
        var invite = await graphClient.Invitations.Request().AddAsync(invitation);
        return invite;

    With this, how does it even know what Event it's sending an invitation for? Is the InviteRedirectUrl generated unique? Any help would be greatly appreciated.

    Wednesday, August 21, 2019 9:24 PM


All replies

  • User753101303 posted


    It seems you are trying to invite a user whose account is (or should be) under your control (for example created directly in your Azure AD or kept in sync from an on premise directory owned by your organization or maybe a non existing account whose mail ends with your own on premise domain name etc...). Use https://portal.azure.com/#blade/Microsoft_AAD_IAM/UsersManagementMenuBlade/AllUsers and see if you find the user you are trying to invite.

    It's not an invitation to an "event". This to invite external users to register themselves inside your own Azure AD tenant so that they can access your own resources using an account which is not under your control. It creates immediately a "guest" account (to which you can  immediately assign permissions etc...) which will be enabled once the user completed the registration process. Depending on the situation the user will be able then to just use his existing company or Microsoft account (or at worst will have to create a new Microsoft account).

    Thursday, August 22, 2019 12:20 AM
  • User1314407993 posted

    I'm still a bit confused. I did a search on inviting others to a calendar event, and the code I showed in my post is what I found. But that's to invite them to share account control? If it's to assume control over my account's resources, then why does the Invitation take an InviteRedirectUrl as part of the Invitation object? Here's the article I was referencing: Send Event Invitation

    So far my application:

    1. Sends emails as the currently logged-in user, and places the email in their Outlook "Sent Items" folder. 
    2. Creates a Calendar Event in the logged-in user's Outlook Calendar, setting the Attendee to the logged-in user.

    My application has sufficient permissions to perform these tasks, but I'm having difficulty sending invitations to other users. If the article I found wasn't for this, could you suggest another? 

    Thursday, August 22, 2019 4:23 PM
  • User753101303 posted

    Nope. As said on this page "Invitation adds an external user to the the organization"' and check the parent "Invitation Manager" page.

    Instead see rather around https://docs.microsoft.com/en-us/graph/api/user-post-events?view=graph-rest-1.0&tabs=http or maybe https://en.wikipedia.org/wiki/ICalendar for a general audience.

    • Marked as answer by Anonymous Thursday, October 7, 2021 12:00 AM
    Thursday, August 22, 2019 6:24 PM
  • User1314407993 posted

    Thanks. You were 100% correct. Turned out the trick was to include an organizer to the meeting, and all attendees are then sent an invitation email. I went off on the completely wrong tangent. 

    Thursday, August 22, 2019 11:44 PM