SecCertificateAddToKeychain - Unknown format in import

The funcion SecCertificateAddToKeychain() gives me an error with the certificate I created for testing.

The certificate - TestCert.p12:

openssl req -x509 -newkey rsa:4096 -keyout key.pem -out cert.pem -days 365
openssl pkcs12 -export -inkey key.pem -in cert.pem -out TestCert.p12

The code:

NSData  *certData = [NSData dataWithContentsOfFile:path];
if (certData)  {
   SecCertificateRef  newCert = SecCertificateCreateWithData (NULL, (CFDataRef)certData);
   if (newCert)  {
      OSStatus  addResult = SecCertificateAddToKeychain (newCert, NULL);
      if (addResult)  {
         NSString  *errStr = SecCopyErrorMessageString (addResult, NULL);
         NSLog (@"Cannot add certificate to keychain: %@", errStr);
      }
   }
}

Output: Cannot add certificate to keychain: Unknown format in import. Any idea?