500 error with php 5.6

Hi, it could potentially be the case of having a lot of posts where PHP is timing out.

The best solution in this aspect is to actually run the queries within phpMyAdmin.

Please make sure you back up your database before running the below.

Could you please delete the full text indexes again and run this in phpMyAdmin:

ALTER TABLE wp_posts DROP INDEX crp_related;
ALTER TABLE wp_posts DROP INDEX crp_related_title;
ALTER TABLE wp_posts DROP INDEX crp_related_content;
ALTER TABLE wp_posts ADD FULLTEXT crp_related (post_title, post_content);
ALTER TABLE wp_posts ADD FULLTEXT crp_related_title (post_title);
ALTER TABLE wp_posts ADD FULLTEXT crp_related_content (post_content);

You can find the related posts indices at the bottom of the Browse view of the table in phpMyAdmin.

You need to use the correct prefix i.e. wp_ for your table. Some plugins allow you to change it to something else.

The first three lines remove the indexes and the next three create them