Use of undefined constant NONCE_SALT
Use of undefined constant NONCE_SALT ... in Shortcode.php on line 192
Cause & solutionThe problem will be related to a missing constant in your wp-config.php file. This file should contain an automatically generated "NONCE_SALT" constant as you see here in the sample wp-config.php file:
at this line:
define('NONCE_SALT', 'put your unique phrase here');
In your case this seems to be missing for some reason. You should generate a new one:
and enter it into the wp-config.php file as you saw above and that will fix the problem!