ERROR_FORMS_AUTH_REQUIRED - 224 (0xE0)
Access Denied. Before opening files in this location, you must first add the web site to your trusted sites list, browse to the web site, and select the option to login automatically.
Updated: Feb 21, 2026
Technical Meaning
The error code ERROR_FORMS_AUTH_REQUIRED indicates that access to a resource is denied because the web site requires forms-based authentication. This typically occurs when attempting to open files or navigate to a location on a website that demands user authentication but has not been added to the trusted sites list in Internet Explorer settings.
Error Details
This error is specific to scenarios where a web application uses forms-based authentication, such as ASP.NET applications. The system requires the site to be explicitly trusted and authenticated before allowing access to certain resources or locations within the website.
Usage Context
The context for this error typically involves accessing protected content on a web server that employs forms-based authentication mechanisms. This can include downloading files from a secure location, navigating through restricted directories, or attempting operations that require user credentials.
Developer Interpretation
Developers should interpret this error as an indication that the application environment is not properly configured to handle the required authentication process. To resolve the issue, users must add the web site to their trusted sites list and authenticate themselves before performing any actions that require forms-based authentication.
Related Errors
ERROR_INTERNET_LOGIN_REQUIRED(1224, 0x4B8)ERROR_NOT_TRUSTED_SERVER_CERTIFICATE(1223, 0x4B7)
FAQ
Q: Why am I getting this error?
A: The web site you are trying to access requires forms-based authentication. You need to add the site to your trusted sites list and authenticate yourself before proceeding.
Q: How do I resolve this issue?
A: Add the web site to your Internet Explorer trusted sites list, navigate to the site, and log in as required.
Summary
The ERROR_FORMS_AUTH_REQUIRED error occurs when a web application demands forms-based authentication but has not been added to the user's trusted sites list. This is a common scenario for secure web applications that require user credentials before granting access to certain resources or directories.