You can use this plugin to delete comments…WPCommentCleaner
Here is a method to mass delete spam comment in wordpress using phpMyAdmin and by using a plugin.
You can mass delete spam comments, approved comments, un approved comments and trash comments with just one click.
Thanks for your reply
By the way i use VPS server with hostgator. Now i get even more problems like Google fonts not displaying, wp-admin page shows error http request and sometimes it shows host error but my other sites in same server without cloudflare works good.
I have made ticket request. Pls make me resolve this.