Order Cancellation Email Not Going to Customers

Dear Support,

This is to inform that suddenly the order cancellation emails are not delivered to customers when order status is changed to Cancelled. I tried different combinations to get the order cancellation but it is not working for me. it was working earlier. I tried it with send order email option available at the right col. As admin and CC mail I am getting the order cancellation mail. But as customer, I am not getting the manual or auto order cancellation email.

Please suggest what to do.

Warm Regards,
Niraj