This article only applies to Office 365 customers who have a hybrid deployment of on-premises Exchange Server and Exchange Online.
You try to use the Microsoft Remote Connectivity Analyzer tool to send an HTTP request to test the authentication methods of the specified service in Office 365 or in the Exchange hybrid server. If a 401 unauthorized response is received, the Remote Connectivity Analyzer tool expects certain WWW-Authenticate headers in the response. Certain services, such as Microsoft Exchange ActiveSync and Outlook Anywhere (formerly known as RPC over HTTP), don't negotiate an authentication method with the remote server. These clients have a predefined authentication method that's sent with each request. If this authentication method isn't enabled on the remote server, you get the following error message from the Remote Connectivity Analyzer tool:
All Required Authentication Methods could not be found.
Additionally, if the predefined authentication method isn't enabled on the remote server, users may experience the following issues:
- Mobile device users who try to connect by using Exchange ActiveSync can't connect.
- Microsoft Outlook users may be unable to connect by using Outlook Anywhere.
To resolve this issue, follow these steps, as appropriate for your situation:
- If your organization is set up in an Office 365 hybrid deployment scenario that has a mix of on-premises and cloud mailboxes, follow these steps:
- Confirm that Basic authentication is enabled on the Exchange ActiveSync virtual directory under Microsoft-Server-ActiveSync virtual directory in the Exchange Management Console and in Internet Information Server (IIS) on the hybrid server.
- Confirm that Basic authentication is enabled on the remote procedure call (RPC) virtual directory in IIS for Outlook Anywhere users.
Note This authentication method should be managed through the Set-OutlookAnywhere cmdlet and not directly in IIS.
- If your organization isn't set up in an Office 365 hybrid deployment scenario, and all the mailboxes exist only online, follow these steps:
- Confirm that Basic authentication is selected under Exchange Proxy Settings in Microsoft Outlook. This setting should match the authentication method that you enabled in IIS.
- If this setting is obtained through Autodiscover, make sure that the ClientAuthenticationMethod parameter or the DefaultAuthenticationMethod parameter is specified correctly on your Outlook Anywhere configuration.
Review the following documentation and confirm that the correct authentication methods for each application or service are enabled for the virtual directories on your Microsoft Exchange Server:
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