Thanks @rankmath
I use default editor on wordpress. I load Classic editor just now. The problem has disappeared.
But I dont use Classic editor.
The following error appears when adding a new post after you passive the classic editor
Fatal error: Cannot use RankMath\Helper as Helper because the name is already in use in /home/selimoz2/public_html/wp-content/plugins/seo-by-rank-math/includes/rest/class-post.php on line 19
Fatal error: Class ‘PasswordHash’ not found in /home/selimoz2/public_html/wp-includes/class-wp-recovery-mode-key-service.php on line 53
