Check out your update_post_meta
variables.
It should be: update_post_meta($post_id, $meta_key, $meta_value, $prev_value);
Here $prev_value
is optional. Full details here
Check out your update_post_meta
variables.
It should be: update_post_meta($post_id, $meta_key, $meta_value, $prev_value);
Here $prev_value
is optional. Full details here