How to force form-based authentication in Enterprise Manager

Challenge

In v9 of Enterprise Manager, you might get an authentication prompt similar to the one below (the look of the prompt depends on your internet browser).
To force the use of HTML form-based authentication, use the solution below.

Cause

The window is shown due to the automatic NTLM-based authentication method introduced in v9.

Solution

1. Open the Internet Information Services (IIS) Manager console on your Enterprise Manager server.
2. Locate the VeeamBackup site.
3. In the Default Document options, add Login.aspx to the top of the list.
4. In the Authentication options, disable Forms Authentication method.
5. In the Modules, remove the MixedAuthenticationModule2 module.

More Information

Alternatively, you can go directly to the page at https://enterprise-manager:9443/login.aspx.

NTLM-based method automatically logs in the current user if the following conditions are met:
1) The computer you are using to access Enterprise Manager and EM itself are in the same AD domain
2) The user has permissions to access Enterprise Manager