ERR_SSL_KEY_USAGE_INCOMPATIBLE Error and How to Fix It

Have you ever experienced the ERR_SSL_KEY_USAGE_INCOMPATIBLE error while setting up HTTPS and wondered why your valid SSL certificate still fails? These connection errors do not always occur because certificate is expired or revoked; it is mainly due to numerous subtle misconfigurations that make valid certificates ineffective. It indicates a possible mismatch between key usage attributes of the certificates and the function it is trying to perform. This browser warning often leaves users locked out since it prevents HTTPS connections. Understanding the root cause of this issue and solving it is critical for Web Administrators, DevOps Engineers, and IT Security Teams. This detailed blog will explain the technical foundation of the error and provide step-by-step fixes to resolve it. What is the ERR_SSL_KEY_USAGE_INCOMPATIBLE Error? The ERR_SSL_KEY_USAGE_INCOMPATIBLE error is a browser-enforced SSL/TLS validation failure. It happens when the certificate’s declared usage permissions don’t align with how it is being used or intended to be used in the connection. This means that the SSL certificate is being used for things like authenticating a web server or a client. While it is not technically configured to act in such a way. When the browser initiates an SSL/TLS handshake, the client and server not only […]