Different number of posts in regular loop and CPT category page

You’re halfway there. All you’re missing is the right hook:

add_action( 'pre_get_posts', 'num_posts_archive_project_ie' );

The pre_get_posts hook fires after the main WP_Query object is instantiated but before it’s sent to the DB.

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