Admin Emails are not Sending

My donors receive their emails
Dear [FIRST_NAME][LAST_NAME]
Thanks for making donation on our site. Your donation detail is as follow :
[DONATION_DETAIL]
Regards.

However the admin does not send
Dear administrator ! You got new donation on your site . The donation detail is as follow : [DONATION_DETAIL]

I tried sendmail and PHP

Hi Calvin,
Please submit ticket and send your site url with super admin account. I'll check the issue for you
Thanks
Dam