(Solved) 403.16 Forbidden: Client certificate is untrusted or invalid

A browser displays 4xx error when there is a client side issue while accessing a website. Specifically, 403 error translates into “Forbidden“. If you dive deep in the issue (Failed Request Logs or IIS logs), you may see 16 as a sub-status code which refers to “Client certificate is untrusted or invalid” (Reference).

You will find out about how to solve 403.16 error in this post.