Getting errors in error_log file

I’ve changed the actual post title with POST_TITLE and actual post content with POST_CONTENT.

[21-May-2021 08:41:16 UTC] WordPress database error Can’t find FULLTEXT index matching the column list for query insert into wp_yarpp_related_cache (reference_ID,ID,score) SELECT 2922 as reference_ID, ID, ROUND(0 + (MATCH (post_content) AGAINST (‘POST_CONTENT’)) * 1 + (MATCH (post_title) AGAINST (‘POST_TITLE’)) * 1 + count(distinct if( terms.term_taxonomy_id in (105,112), terms.term_taxonomy_id, null )) * 3 + (1 = 0) * 1,4) as score
from wp_posts
left join wp_term_relationships as terms on ( terms.object_id = wp_posts.ID )
where post_status in ( ‘publish’, ‘static’ ) and post_password =” and post_type IN (‘post’) AND wp_posts.ID NOT IN (2922)
group by ID
having score >= 4.000000 and ID != 0 order by score desc limit 10 on duplicate key update date = now() made by require(‘wp-blog-header.php’), require_once(‘wp-includes/template-loader.php’), include(‘/themes/generatepress/single.php’), generate_do_template_part, get_template_part, locate_template, load_template, require(‘/themes/generatepress/content-single.php’), the_content, apply_filters(‘the_content’), WP_Hook->apply_filters, ezTOC::the_content, ezTOC::get, ezTOC_Post::get, ezTOC_Post->__construct, ezTOC_Post->applyContentFilter, apply_filters(‘the_content’), WP_Hook->apply_filters, YARPP->the_content, YARPP->display_basic, YARPP->display_related, YARPP_Cache->enforce, YARPP_Cache_Tables->update, YARPP_Cache->query_safely

[21-May-2021 08:41:16 UTC] WordPress database error Can’t find FULLTEXT index matching the column list for query insert into wp_yarpp_related_cache (reference_ID,ID,score) SELECT 2922 as reference_ID, ID, ROUND(0 + (MATCH (post_content) AGAINST (‘POST_CONTENT’)) * 1 + (MATCH (post_title) AGAINST (‘POST_TITLE’)) * 1 + count(distinct if( terms.term_taxonomy_id in (105,112), terms.term_taxonomy_id, null )) * 3 + (1 = 0) * 1,4) as score
from wp_posts
left join wp_term_relationships as terms on ( terms.object_id = wp_posts.ID )
where post_status in ( ‘publish’, ‘static’ ) and post_password =” and post_type IN (‘post’) AND wp_posts.ID NOT IN (2922)
group by ID
having score >= 4.000000 and ID != 0 order by score desc limit 10 on duplicate key update date = now() made by require(‘wp-blog-header.php’), require_once(‘wp-includes/template-loader.php’), include(‘/themes/generatepress/single.php’), generate_do_template_part, get_template_part, locate_template, load_template, require(‘/themes/generatepress/content-single.php’), the_content, apply_filters(‘the_content’), WP_Hook->apply_filters, YARPP->the_content, YARPP->display_basic, YARPP->display_related, YARPP_Cache->enforce, YARPP_Cache_Tables->update, YARPP_Cache->query_safely