{"id":2735,"date":"2025-02-05T08:28:43","date_gmt":"2025-02-05T08:28:43","guid":{"rendered":"https:\/\/certera.com\/kb\/?p=2735"},"modified":"2025-02-05T08:28:44","modified_gmt":"2025-02-05T08:28:44","slug":"how-to-fix-err_ssl_key_usage_incompatible-error","status":"publish","type":"post","link":"https:\/\/certera.com\/kb\/how-to-fix-err_ssl_key_usage_incompatible-error\/","title":{"rendered":"How to Fix ERR_SSL_KEY_USAGE_INCOMPATIBLE Error?"},"content":{"rendered":"\n

What is ERR_SSL_KEY_USAGE_INCOMPATIBLE Error?<\/h2>\n\n\n\n

ERR_SSL_KEY_USAGE_INCOMPATIBLE is an SSL\/TLS error that signifies a conflict between the indicated SSL\/TLS certificate<\/a> and key usage attributes or intended use.<\/p>\n\n\n\n

This normally occurs wherein the key usage extensions of the certificate do not permit the operation under implementation during the SSL handshake process.<\/p>\n\n\n\n

For instance<\/strong>, a certificate designed to be used for server authentication requires certain key usage attributes to be marked, including the digital signature and key encipherment.<\/p>\n\n\n\n

If these attributes are not set or otherwise set incorrectly, the SSL\/TLS handshake doesn\u2019t happen and that leads to ERR_SSL_KEY_USAGE_INCOMPATIBLE error.<\/p>\n\n\n\n

Causes of ERR_SSL_KEY_USAGE_INCOMPATIBLE Error<\/h2>\n\n\n\n

The ERR_SSL_KEY_USAGE_INCOMPATIBLE error can occur due to several causes related to the configuration and usage of SSL\/TLS certificates. Here are some common causes:<\/strong><\/p>\n\n\n\n

1. Incorrect Key Usage Extensions<\/h3>\n\n\n\n

This error is commonly traced back to improper settings of key usage extensions in SSL\/TLS certificates.<\/p>\n\n\n\n

Every certificate must contain information on what kind of usage is allowed for that particular certificate, such as server authentication\u2019s Digital Signature and Key Encipherment.<\/p>\n\n\n\n

If these extensions are missing or set improperly, the SSL\/TLS handshake fails<\/a> and the error is raised, as is shown below.<\/p>\n\n\n\n

2. Mismatched Certificate Purposes<\/h3>\n\n\n\n

It comes in handy especially for specific uses like server authentication or client authentication or even code signing. This is the error that can happen when a certificate is being used for a purpose different from the one intended.<\/p>\n\n\n\n

For example<\/strong>, when trying to authenticate a server using a client certificate, you will get the error \u2018This server certificate is not for client use and this client certificate is not for server use and this client certificate is not for server use \u2019 which corresponds to ERR_SSL_KEY_USAGE_INCOMPATIBLE.<\/p>\n\n\n\n

3. Improper Certificate Chain Configuration<\/h3>\n\n\n\n

In this type of connection, the SSL\/TLS handshake process<\/a> entails checking the certificate chain starting from the server certificate through to the root certificate.<\/p>\n\n\n\n

It can happen if there are misconfigurations involved with the intermediate certificates or the root certificate or if the key usage extensions are missing in it.<\/p>\n\n\n\n

4. Expired or Revoked Certificates<\/h3>\n\n\n\n

The error may also occur when the certification authority has issued some certificates that have expired, have been revoked, or are not trusted by the operating system.<\/p>\n\n\n\n

Also Read:<\/strong> What happens when your SSL Certificate Expires?<\/a><\/p>\n\n\n\n

Although the kind of error that would be returned when the certificate has expired or the certificate authority has revoked the certificate might not be the same, this key usage incompatibility is one that can cause this error when it occurs during the validation process.<\/p>\n\n\n\n

How to Fix SSL_KEY_USAGE_INCOMPATIBLE Error?<\/h2>\n\n\n\n

Create a Trusted Self-Signed Certificate<\/h3>\n\n\n\n