# /mailer/amazon\_api/callback error 400 **URL:** \ **Category:** Product Support\ **Tags:** mautic-4\ **Created:** [December 3, 2021, 9:25am UTC](https://forum.mautic.org/t/mailer-amazon-api-callback-error-400/21886 "2021-12-03T09:25:28Z")\ **Posts on this page:** 3\ **Page:** 1
**Author:** ![erwan](https://sea2.discourse-cdn.com/flex020/user_avatar/forum.mautic.org/erwan/32/6306_2.png) [@erwan](https://forum.mautic.org/u/erwan)\ **Post date:** [December 3, 2021, 9:25am UTC](https://forum.mautic.org/t/mailer-amazon-api-callback-error-400/21886/1 "2021-12-03T09:25:28Z")
**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](http://mautic.site.com/mailer/amazon_api/callback), page return a **400** Bad Request ```auto Can't see why. Mautic is hosted on ec2 instance amazon sns is validated (not in pending) ``` ---
**Author:** ![joeyk](https://sea2.discourse-cdn.com/flex020/user_avatar/forum.mautic.org/joeyk/32/11164_2.png) [@joeyk](https://forum.mautic.org/u/joeyk)\ **Post date:** [December 3, 2021, 11:26am UTC](https://forum.mautic.org/t/mailer-amazon-api-callback-error-400/21886/2 "2021-12-03T11:26:31Z")
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. ---
**Author:** ![erwan](https://sea2.discourse-cdn.com/flex020/user_avatar/forum.mautic.org/erwan/32/6306_2.png) [@erwan](https://forum.mautic.org/u/erwan)\ **Post date:** [December 6, 2021, 9:28am UTC](https://forum.mautic.org/t/mailer-amazon-api-callback-error-400/21886/3 "2021-12-06T09:28:09Z")
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