Exclude posts based on meta value

post__not_in function is for exclude categoryes. Try with:

$query = new WP_Query( 'post__not_in' => array( 2, 5, 12, 14, 20 ) );

maybe your problem is in syntax

Hata!: SQLSTATE[HY000] [1045] Access denied for user 'divattrend_liink'@'localhost' (using password: YES)