No email received on Order status changed from Cancelled to Processing

Hi Support,

We have received an interesting successful order which the status is changed from Cancelled to Processing and the payment is successfully received but there is no email being sent to admin.

Print Screen: https://snag.gy/m3NlTa.jpg

Here are my questions:
1. Why is the cancelled order able to be reprocess back?
2. Why is the Order failed to generate email from Cancelled to Processing. How do i able to send an email on this?

Appreciate for any help. Thanks.