Keytool error: java.lang.Exception: Input not an X.509 certificate

The "keytool error: java.lang.Exception: Input not an X.509 certificate" is a common error message encountered when using the Java Keytool utility to manage SSL/TLS certificates.

This error occurs when the Keytool utility is unable to parse the certificate file as a valid X.509 certificate. X.509 is a standard for digital certificates that is widely used in SSL/TLS and other Internet security protocols.

This error can be caused by several issues, including:
  1. The certificate file is in the wrong format
  2. The certificate file is corrupt or has been modified
  3. The certificate file is not a valid X.509 certificate
  4. The certificate file is not the correct file for the operation being performed
To resolve this issue, you should first verify that you are using the correct certificate file and that it is in the correct format. Common certificate formats include .cer, .crt, and .pem. Also, you should check that the certificate is not corrupted or has not been modified.

If you are sure that the certificate is valid and in the correct format, you may need to use a different tool to import the certificate, or you may have to contact your certificate authority for assistance.

It is also important to note that you should always keep the backup of your certificate and private key in a safe place, in case of any issues like this.