Check for parent category

The correct syntax of cat_is_ancestor_of is

cat_is_ancestor_of( $parent_cat_id, $child_cat_id );

Where:

$parent_cat_id: should be the id to check if this is the parent category, in your case it should be 526.

$child_cat_id: should be the id of the child category.

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