Exception while processing email invitation : The invited user already exists in the directory

Question

I have the below code written in c#, and using Micorosoft Graph API

   //Get redemption URL
            var invitation = new Invitation
            {
                InvitedUserEmailAddress = "<email address>",
                InviteRedirectUrl = "<Redirect URL>",
                SendInvitationMessage = false,
            };
            var inviteResponse = graphClient.Invitations
                .Request()
                .AddAsync(invitation).Result;

I see following error in the log

ProcessEmailInvitation - Exception while processing email invitation: One or more errors occurred. (Code: BadRequest Message: The invited user already exists in the directory as object ID: xxxxx-xxxxxx-xxxxxxxxx-xxxxxxxxx.

Is it anything to do with SendInvitationMessage parameter?

I tried to change the code as follow,

 var inviteResponse = Task.Run(async () => await graphClient.Invitations.Request().AddAsync(invitation).Result);

but it says

Microsoft.Graph.Invition is not awaitable.

Answer 1

The error indicated that you may invite a user who is already be invited into your tenant, you may test with another email account. And pls allow me to post a sample code here for a better look. If it doesn't help you I'll delete it. By the way SendInvitationMessage is false by default according to the api document.

public async Task<string> inviteUserAsync() {
    var invitation = new Invitation
    {
        InvitedUserEmailAddress = "[email protected]",
        InviteRedirectUrl = "https://www.google.com"
    };
    await _graphServiceClient.Invitations.Request().AddAsync(invitation);
    return "success";
}