Hi guys!
Previously I created some ticketing system that working just fine.
I don't know why for this new ticketing system that I just created in Jira, the notification that sent out to the client receiving this notification.

I have read some articles that saying to add SPF records under our DNS domain.
But I'm not sure whether this solution of adding the SPF record will be resolving this issue and my boss doesn't want to wait for another email to proving whether the SPF solution will be resolving the issue or not.
Do you guys have any idea on how to resolving this issue? any comment would be so much help for me.
Thank you in advance!