A notification is sent to the store contact or a designated Admin user if the payment method selected during checkout fails to complete the transaction.
Make sure that you have updated the needed email template to reflect your brand. For a complete list of templates, see Email Template List.
On the Admin sidebar, go to Stores > Settings > Configuration.
On the left panel, expand Sales and choose Checkout.
Expand the Payment Failed Emails section.
Set the options for payment failed emails:
For Send Payment Failed Email Copy To, enter the email address of anyone who is to receive a copy of the payment failed notification.
If sending a copy to multiple recipients, separate each address with a comma.
Set Payment Failed Copy Method to one of the following:
Bcc- Sends a blind courtesy copy by including the recipient in the header of the same email that is sent to the customer. The BCC recipient is not visible to the customer.
Separate Email- Sends the copy as a separate email.
Click Save Config.