Develop Reference

How can we access the exchange mailboxes via EWS when the user has no own mailbox?

We want to access mailboxes via EWS (Exchange Web Services) with an dedicated user who has no own mailbox.
The target is to cover all Exchange Server version 2007-2019.
Reason why we want to have an dedicated user with no mailbox: We want analyze all mailboxes in an Exchange Server by an software. But therefore we not really need an user and even an mailbox. Only the data inside the mailboxes are interesting for the software.
We use Independentsoft´s API to access the EWS:
var lCredential = new NetworkCredential("ADUserWithNoMailbox", "Password");
m_Service = new Service("https://hostname/EWS/Exchange.asmx", lCredential);
try
{
FindFolderResponse lResponse = m_Service.FindFolder(StandardFolder.MailboxRoot);
// [...]
}
catch (Exception e)
{
// cast in into multiple expected types
var lServiceRequestException = e as Independentsoft.Exchange.ServiceRequestException;
if (lServiceRequestException.ResponseCode == "ErrorNonExistentMailbox")
{
// lServiceRequestException.Message shows: "No mailbox with such guid."
// [...]
}
// [...]
throw;
}
Our user ADUserWithNoMailbox which is in the Active Directory has no mailbox. Therefore an exception occurs with the message:
"No mailbox with such guid."
Question: How can we access the exchange mailboxes via EWS when the user has no own mailbox?

It should work okay if the servers are patched to the correct levels eg there can be problem like https://support.microsoft.com/en-us/topic/-the-smtp-address-has-no-mailbox-associated-with-it-error-when-you-access-a-user-s-mailbox-by-using-ews-application-c8e31e36-b6e2-229e-cc78-305ab9fea94a. I've always found this to be problematic if your deploying apps in different customer environments and found for most OnPrem deployments giving the Service account your using a Mailbox is not a problem, to stop it appearing in address lists most customers can just hide it. (Office365 is a different matter because of the cost of consuming a licence but you can use App tokens which don't require a user or mailbox)
Probably for your requirement using EWS Impersonation https://learn.microsoft.com/en-us/exchange/client-developer/exchange-web-services/impersonation-and-ews-in-exchange is a better option as that will give you access to all Mailboxes.

The specified object was not found in the store., The process failed to get the correct properties

I'm trying to achieve folder from a user with an admin user (just for test)
ExchangeService service = new ExchangeService(ExchangeVersion.Exchange2013_SP1);
service.Credentials = new WebCredentials("AdminUsername", "AdminPass");
service.AutodiscoverUrl("UserItryToImpersonate#domain.com", RedirectionUrlValidationCallback);
//creates an object that will represent the desired mailbox
Mailbox mb = new Mailbox(#"UserItryToImpersonate#domain.com");
// Create Calendar object for testing
CalendarFolder folder1 = new CalendarFolder(service);
folder1.DisplayName = "UserItryToImpersonate#domain.com";
folder1.Save(WellKnownFolderName.Calendar);
FolderId rootCalendarFolder = new FolderId(WellKnownFolderName.Calendar, "UserItryToImpersonate#domain.com");
UserConfiguration.Bind(service, "CategoryList", rootCalendarFolder, UserConfigurationProperties.All); //// error here....
That error is happening because the user I try to impersonate is a new user and never log in to OWA even once...
when I logged into OWA it worked...
How can I bypass that...
How can I create the objects from remote???
Most of the Topics say it Permissions Error... but I sure I have the permissions...
That problem solved when I take permission and enter OWA as impersonate him...
thank you in advance

That error is happening because the user I try to impersonate is a new user and never log in to OWA even once... when I logged into OWA it worked...
It sounds like the Mailbox hasn't been provisioned and logging into OWA is just kicking off that process. Using EWS alone won't do the provisioning the easiest way it just send an Email to the Mailbox. Another method I've used in the past is if you run Test-MapiConnectivity https://learn.microsoft.com/en-us/powershell/module/exchange/mailboxes/test-mapiconnectivity?view=exchange-ps from the Exchange Management Shell before you run your EWS code that will always ensure that the Mailbox has been provisioned.

Accessing Exchange shared folders using Mailkit

I am creating an application to read emails and attachments from an account on a Microsoft hosted Exchange server (Office 365). The difficulty I'm having is that I cannot find a way to get the MailKit API to see shared folders on the email account that I have connected to.
I can connect to my email account and see my Inbox and other folders that are under my main account. In Outlook, the tree-view of folders shows my main account (associated with my main email address) in the root, with the Inbox and other folders under that account. Outlook then shows my shared folder name (associated with another email address) also starting at the root, with it's Inbox and other folders under it. The shared folder (with its associated email address) does not actually have its own Exchange account to connect to.
When connected, I have examined the ImapClient.SharedNamespaces and ImapClient.Others collections and they are both empty.
Is there a way to see this type of shared folder in Exchange with MaikKit?

This is possible by appending a backslash and the shared mailbox alias to the end of the username during authentication, here's some example code...
void Main()
{
var userName = "main#user.com"; // The email address that has permissions to the shared mailbox
var sharedMailboxAlias = "aliasName"; // This is the alias name as setup in Exchange
var password = Util.GetPassword("Office365Password"); // Util.Password is a LinqPad method
using (var client = new ImapClient())
{
client.Connect("outlook.office365.com", 993, true);
client.Authenticate(userName + #"\" + sharedMailboxAlias, password);
var inbox = client.Inbox;
inbox.Open(FolderAccess.ReadOnly);
Console.WriteLine("Total messages: {0}", inbox.Count);
Console.WriteLine("Recent messages: {0}", inbox.Recent);
client.Disconnect(true);
}
}
The shared mailbox alias usually defaults to the left part of the email address before the #
Updated: As per #Nischo comment - removing XOAUTH2 is no longer required. For more details: https://github.com/jstedfast/MailKit/issues/566
So removed the following line as it's no longer
client.AuthenticationMechanisms.Remove("XOAUTH2");

The answer by Sean on Jan 17 is correct. Note that you MUST remove the XOATH2 authentication as Office 365 does not support it even though it says it does when you first connect. MailKit then tries to use XOAUTH2 and has an internal exception when it fails to work. This is probably a bug in MailKit.

Accessing a generic process inbox using EWS

I am trying to use EWS to access a process mailbox. For some automated queries we created a genric process mailbox. I want to parse emails by watching the Process inbox.
My code was working earlier with the old exchange server. But after migration to office 365 it fails.
I am able to access my mailbox and parse on the office 365 using my credentials.
How do I access this process mailbox? Earlier I create an ExchangeService and connect to the process email address with UseDefaultCredentials = true.
I set the AutoDiscoverURl and used DefaultCredentials. But When I tried to read emails I get "The SMTP address has no mailbox associated with it."
EDIT:
I tried to use my own credentials instead of the Default Credentials.
string smtpaddress = "somesharedsmtp#domain.com";
es.Url = new Uri("https://outlook.office365.com/EWS/Exchange.asmx");
es.Credentials = new WebCredentials("myemail", "mypassword");
es.AutodiscoverUrl(smtpaddress, RedirectionCallback);
FolderId SharedMailbox = new FolderId(WellKnownFolderName.Inbox, "somesharedsmtp#domain.com");
Folder sharedInbox = Folder.Bind(es, SharedMailbox);
At this point I can check sharedInbox containing the details of the Inbox. I can see the unread email count and others.
But when I access
ItemView itemView = new ItemView(100);
FindItemsResults<Item> findResults1 = es.FindItems(pqInbox.Id, itemView);
I get exception "SMTP address has no mailbox associated with it"

disclaimer: I haven't worked with EWS in a while.
You can't use the default credentials for Office 365. You'll need to provide either the basic credential or use an OAuth token.
You should confirm that the account was migrated to Office 365. Login to OWA and look at the URL to make sure you are using Office 365 and not an on-premise server.
This was already answered by Exchange Web Services: UseDefaultCredentials property

How to use EWS on hosted Exchange with Impersonation?

I want to create a service which to crawl all inboxes of all users on a hosted exchange server (“myclient.onmicrosoft.com”) via EWS.
This already works well when I connect to on-premise exchange servers in the same domain. But when I try to connect this service to a hosted exchange, it throws 401 (wrong authorization) errors. Of course, this is a different domain as the hosted exchange server.
My service runs on an on-premise server and uses a “god-mode” user to impersonalise to all active directory users. My question is: How to connect the users of my on-premise system correctly to the hosted exchange in a different domain?
Note: It works when I use the credentials directly and the impersonation way does work on on-premise installations.
What I did so far (and I wonder of this is the right way to do it): On our on-premise server I created a domain “myclient.onmicrosoft.com” just like on the hosted server and an AD user with the same name and password as on the hosted exchange (called “mytest#myclient.onmicrosoft.com”).
On my crawler service I did:
I got all AD users in our on premise server
var allUsers = SearchAllActiveDirectoryUsers();
foreach (DataRow user in allUsers.Rows)
{
String domainName = (String)user["DomainName"];
String samAccountName = (String)user["SamAccountName"];
String principalName = (String)user["PrincipalName"];
String principalDomainName = (String)user["PrincipalDomainName"];
String mail = (String)user["Mail"];
}
Then for each AD user I connected the user with the exchange service like this:
ExchangeService ex = new ExchangeService(version);
ex.Url = new Uri(“https://outlook.office365.com/EWS/Exchange.asmx”);
ex.Credentials = new WebCredentials("mytest#myclient.onmicrosoft.com", “XXX”, " myclient.onmicrosoft.com");
// THIS DOES WORK CORRECTLY!
ex.ImpersonatedUserId = new ImpersonatedUserId(ConnectingIdType.PrincipalName, “mytest#myclient.onmicrosoft.com”);
//this does NOT work!
Any ideas what I am missing?

You need to use the credentials of your "god-mode" user, but set the ImpersonatedUserId to the AD user. Something like:
ex.Credentials = new WebCredentials("account_with_impersonation_rights#myclient.onmicrosoft.com", "password");
ex.ImpersonatedUserId = new ImpersonatedUserId(ConnectingIdType.PrincipalName, "mytest#myclient.onmicrosoft.com");
When you connect to Office 365 via EWS, you always need to supply credentials. You can't use UseDefaultCredentials = true.