RadarSync Ensures you have the latest drivers and software updates to make your PC run better and safer.
Fix-It Utilities Make your PC run like new! Includes Anti-Virus, Anti-Spyware, hardware diagnostics, registry fixer, and more!
Partition Commander Now it's easy for anyone to safely partition their hard drive! You can reclaim waste disk space, organize files, even add new OSes.
Client certificate is untrusted or invalid
Some web sites require you have a special "certificate" to access the site. This typically occurs with higher security sites, such as a corporate web site for employee access only. It appears you have the certificate, but it not usable.
403.16 - Forbidden: Client certificate is ill-formed or is not trusted by the Web server.
Your client certificate is untrusted or invalid. A Secure Sockets Layer (SSL) client certificate is used for identifying you as a valid user of the resource.
Error messages will differ depending on the web server and if replaced by the web site designers.
Frequency is relative to other Internet warnings and errors.
Solutions and Fixes
Get New Certificate
You will need to contact the web owners to get a new certificate (what is called a client SSL certificate).
FaultWire Staff Posted: 26-Oct-2008
The client browser tries to use a client certificate that is not trusted by the server that is running IIS 7.0 or that is not valid.
"403.16 - Client certificate is untrusted or invalid" is only supported by Microsoft IIS (Internet Information Services) web servers.
The four hundred series of errors indicate something was sent to the remote web server incorrectly.
While we believe this information up to date and accurate, FAQware is not responsible for any inaccuracies. If you find something that is out of date or inaccurate, please let us know at
so we can correct it.