The signature algorithm, public key, or public key parameters are disallowed by local policy (e.g. a weak algorithm or an insufficient key size).

The certificate is expired.

The certificate's key usage is invalid.

The name constraints have been violated, or could not be processed.

Certificate policy validation failed, or a critical policy extension could not be processed.

The signature is invalid.

A processing limit was exceeded (e.g. the maximum number of policy tree nodes).

The certificate does not chain correctly.

The certificate is not a CA certificate.

No acceptable trust anchor found.

The certificate is not yet valid.

The path length constraint has been violated.

The certificate is revoked.

The revocation status of the certificate could not be determined.

The certificate contains one or more unrecognized critical extensions.

Unspecified reason.