WordPress database error Illegal mix of collations

wordpress

#1

I’m getting this error message on my Wordpress installation whenever someone posts a comment (I’ve XXXed out the comment author name and email for privacy) :

WordPress database error Illegal mix of collations (utf8_general_ci,IMPLICIT) and (utf8mb4_general_ci,COERCIBLE) for operation ‘=’ for query SELECT comment_ID FROM wp_55gpvn_comments WHERE comment_post_ID = 6820 AND comment_parent = ‘0’ AND comment_approved != ‘trash’ AND ( comment_author = ‘XXX’ OR comment_author_email = ‘XXX@gmail.com’ ) AND comment_content = ‘???’ LIMIT 1 made by wp_handle_comment_submission, wp_new_comment, wp_allow_comment

Any suggestion what I can do to fix this ?