Warning: Cannot modify header information – headers already sent by…

Hello,

I have the above error as shown below:

WordPress database error: [Table ‘patrimoi_wrdp4.nica_post2cat’ doesn’t exist]
SELECT cat_ID AS ID, MAX(post_modified) AS last_mod FROM nica_posts p LEFT JOIN nica_post2cat pc ON p.ID = pc.post_id LEFT JOIN nica_categories c ON pc.category_id = c.cat_ID WHERE post_status = ‘publish’ GROUP BY cat_ID

Warning: Cannot modify header information – headers already sent by (output started at /home/patrimoi/public_html/nicacadie/wp-includes/wp-db.php:160) in /home/patrimoi/public_html/nicacadie/wp-includes/pluggable.php on line 391

In this line, nicacadie/wp-includes/wp-db.php:160, I have this:

</div>”;

I can’t figure out what’s wrong?

Thanks for your support. Yes, I am reading this page:
https://codex.www.ads-software.com/FAQ_Troubleshooting#How_do_I_solve_the_Headers_already_sent_warning_problem.3F.