/mailer/amazon_api/callback error 400

Your software
My Mautic version is: 4.0.1
My PHP version is:7.4
My Database type and version is:

Your problem
My problem is:
That i can’t get bounce to get back from amazon sns to mautic.
After looking why i saw that whenever i reach mautic.site.com/mailer/amazon_api/callback, page return a 400 Bad Request

Can't see why.
Mautic is hosted on ec2 instance
amazon sns is validated (not in pending)

Because you need to pass the proper payload. If you just open the page and don’t pass the payload you’ll get a 400 bad request.

OK, the json then ?

I will have a look again at documentation see if i haven’t miss anything that can explain the fact that bounce doesn’t shows up in Mautic