We need to disable the Email Bursting at instance level.
Hi Yashdeep,
Kindly go through with the below line and refer the point 'RESTRICT EMAIL DELIVERY DOMAINS'
https://www.oracle.com/webfolder/technetwork/tutorials/tutorial/cloud/r13/wn/common/releases/20B/20B-common-wn.htm#F12783
Fusion BI Publisher: How To Restrict/Allow Outbound Emails To Customer Domains (Doc ID 2763555.1)
Thanks
Khaleel