Custom field linking problem!

What you’re meant to be doing is echoing the $meta_value, not assigning it to a variable.

Also don’t forget to escape the value 🙂

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    <a class="more-link claim-bonus" href="https://wordpress.stackexchange.com/questions/254370/<?php echo( esc_url( get_post_meta( $postID->ID,"tracking_url', true ) ) ); ?>" rel="nofollow" title="">Claim Bonus &raquo; </a>
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