ACF Relationship Posts how to show additional content

Try adding artist ID as the second parameter in the_field(), like so:

<?php the_field('artist_summary', $artist->ID); ?>

http://www.advancedcustomfields.com/resources/functions/the_field/

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