Error when you open an IIS webpage: 403.7 Forbidden: Client certificate required

This article helps you resolve the problem where an unexpected runtime error may be thrown when you open an Internet Information Services (IIS) webpage.

Original product version:   Internet Information Services
Original KB number:   186812


The target audience for this article is website administrators or web developers. If you are an end-user who has encountered this error, we recommend that you ask the site administrator for instructions on how to obtain the correct client certificate.


You have a website that is hosted on IIS. When you go to the website in a web browser, you may receive an error message that resembles the following one:

HTTP Error 403
403.7 Forbidden: Client certificate required


This error occurs when the website requests a client certificate, and then the client either doesn't provide one or the certificate supplied by the client browser is rejected. Client certificates are a kind of Secure Sockets Layer (SSL) certificate typically used to identify a user or computer to a website.

The following are several possible causes of this problem:

  • The root certificate (certification authority certificate) of the client certificate isn't installed on the computer that is running IIS.
  • The client certificate has expired, or the effective time hasn't been reached.
  • The client certificate was revoked.
  • No valid client certificate is available, or a potentially valid client certificate doesn't have an associated private key installed.


Depending on the cause of your problem, try one of the following resolutions:

  • If you don't have a client certificate for the site, and you need one, contact the site administrator for instructions.
  • Check the expiration date and time of the certificate. If your certificate has expired, contact the site administrator for instructions.


Client certificate authentication may be enabled where it is not required. If you intended only to require Transport Layer Security (TLS)/SSL communications, then you need only a server certificate. You can disable client certificate authentication by using the resolution in "HTTP Error 403.7 - Forbidden" error when you run a Web application that is hosted on a server that is running IIS 7.0.

Check whether the server running IIS considers the certificate valid

  1. Export the certificate to a .CER file.
  2. Copy the .CER file to the server that is running IIS.
  3. Open the .CER file on the server that is running IIS.
  4. Look at the Certification Path tab. If all certificates in the chain are displayed without a red cross, then the certificate chain is trusted by the computer. If the root certification authority has a red cross against it, continue to the next set of steps.

Install the root certification authority certificate manually

To resolve this issue, install the root certification authority certificate manually. Follow the following steps:

  1. Select Start, select Run, type mmc, and then select OK.
  2. On the File menu, select Add/Remove Snap-in.
  3. In the Add or Remove Snap-ins dialog box, select Certificates under Available Snap-ins, and then select Add.
  4. In the Certificates snap-in, select Computer account, select Finish twice, and then select OK.
  5. Under Console Root, expand Certificates (Local Computer).
  6. Expand Trusted Root Certification Authorities, and then right-click Certificates.
  7. Select All Tasks, and then select Import....
  8. Select Next, and then navigate to the location where the Root CA certificate file is stored.
  9. After the certificate has been selected, select Next two times, and then select Finish.


Intermediate CA certificates should be installed in the Intermediate Certification Authorities store rather than in the Trusted Roots store. Any certification authority certificate whose Issued by and Issued to values are not the same (and therefore the certificate is not at the top of the hierarchy) is known as an Intermediate CA.