Create event in outlook calendar using Azure AD, getting 401 unauthorized while impersonate to access others calendar.

Question

Dear Experts,

We have scheduler application to create/update calendar events, now we are migrating Modern Authentication. we have registered in Azure and validate token. after token validated, we are impersonate to create/update calendar event, but it shown 401 Unauthorized errors while use the Findfolders method.

try
{
// Make the interactive token request
result = await app.AcquireTokenForClient(ewsScopes)
.ExecuteAsync();

            // Configure the ExchangeService with the access token  
            var ewsClient = new ExchangeService();  
            ewsClient.Url = new Uri("https://outlook.office365.com/EWS/Exchange.asmx");  
            ewsClient.Credentials = new OAuthCredentials(result.AccessToken);  



            //Impersonate the mailbox you'd like to access.  
            //ewsClient.ImpersonatedUserId = new ImpersonatedUserId(ConnectingIdType.SmtpAddress, "admin@xxxx.onmicrosoft.com");  
            ewsClient.ImpersonatedUserId = new ImpersonatedUserId(ConnectingIdType.SmtpAddress, "admin@xxxx.onmicrosoft.com");  

            //Include x-anchormailbox header  
            ewsClient.HttpHeaders.Add("X-AnchorMailbox", "admin@toyotaap.onmicrosoft.com");  

            
            // Make an EWS call  
            **var folders = ewsClient.FindFolders(WellKnownFolderName.MsgFolderRoot, new FolderView(10));**  
            foreach (var folder in folders)  
            {  
                Console.WriteLine($"Folder: {folder.DisplayName}");  
            }  
        }  

From above code the given line got 401 error.

var folders = ewsClient.FindFolders(WellKnownFolderName.MsgFolderRoot, new FolderView(10));

Azure Permission for reference.

Please help to give me idea to resolve this issue.

Answer 1

@Sathish Bonifash , I guess, here you need to use the Microsoft Graph API to create the User's outlook calendar. You can use the following doc to get more understanding on the API, https://learn.microsoft.com/en-us/graph/api/calendar-post-events?view=graph-rest-1.0&tabs=http

Also, would like to state that when you use this API, you would have to fetch a token from AAD as a user, and only that user can use that token to create a calendar for himself/herself.

In the case of shared calendars only, someone else can create a calendar event for someone else.

Hope this helps.

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