From Jonsdocswiki

The Exchange Control Panel, or ECP, is a web based control panel for Exchange 2010 and allows you to:

• Set your Out of office
• Check email delivery (up to the point it leaves the Exchange server)
• Search mailboxes
• Many other administrative functions

Problem

Username or password is incorrect.

When logging in to the Exchange Control Panel (ECP) users are redirected to the logon page and informed their username and password may be incorrect (see right). This happens repeatedly and the user is never presented with the ECP.

Additionally, when a user is logged into OWA and chooses "Set automatic replies" from the options menu they will be presented with the logon page and will also be unable to login.

Solution

These instructions advise how to resolve the problem on Windows Server 2008's version of IIS

It appears that resetting the Exchange virtual directory for ECP has no affect meaning we have to get our hands dirty with Exchange / IIS.First, in the Exchange Management Console, check the Authentication settings on the OWA:

1. Open Exchange Management Console.
2. Expand Server Configuration and click on Client Access.
3. In the central pane, click the Outlook Web App tab.
4. Right click the owa (Default Web Site) item and choose Properties.
5. On the Authentication tab, ensure Use forms-based authentication is ticked.
6. Optionally, specify the logon format (e.g. user name only and click Browse to specify the logon domain).
7. Click OK

You will likely have been told to ensure the ECP settings match those of ECP:

1. Open Exchange Management Console.
2. Expand Server Configuration and click on Client Access.
3. In the central pane, click the Exchange Control Panel tab.
4. Right click the ecp (Default Web Site) item and choose Properties.
5. On the Authentication tab, ensure Use forms-based authentication is ticked.

Re-test access to the ECP. If that doesn't work:

Error when both forms based authentication and Basic authentication are enabled simultaneously.

1. Open Internet Information Services (IIS) Manager.
2. Expand the server node and then expand Sites, Default Website.
3. Click ecp, the central pane will change to say /ecp Home.
4. From the central pane, double click Authentication.
5. Anonymous Authentication and Basic Authentication should be the only enabled options. If Forms Authentication is emabled there will be a warning to the top right (see right) - disabled Forms authentication (right click it and choose disable.

Re-test - the ECP and Automatic replies features should now be working correctly.