```
However, even if it came with a right `from` (putting my email there) it comes back with
```json
{"reject":true,"reason":"Mail to this address is not accepted. Check the address and try to send again?"}
```
So it would’ve rejected that as well…
Am I missing something on the config? I can’t figure it out
---
### Author:  [@tobiaseigen](https://meta.discourse.org/u/tobiaseigen)
#### Post date: [November 12, 2025, 8:37pm UTC](https://meta.discourse.org/t/seeing-smtp-should-reject-400-bad-request-failures-on-bounce-processing/387431/2 "2025-11-12T20:37:38Z")
Hello! Sorry but it appears your topic found no takers. Were you able to resolve your problem on your own?
What mail provider are you using?
---
### Author:  [@DevTeVe](https://meta.discourse.org/u/DevTeVe)
#### Post date: [November 12, 2025, 11:26pm UTC](https://meta.discourse.org/t/seeing-smtp-should-reject-400-bad-request-failures-on-bounce-processing/387431/3 "2025-11-12T23:26:27Z")
No, unfortunately, I am not receiving the bounces…
I am using an SMTP server from a CPanel though
---
### Author:  [@tobiaseigen](https://meta.discourse.org/u/tobiaseigen)
#### Post date: [November 12, 2025, 11:39pm UTC](https://meta.discourse.org/t/seeing-smtp-should-reject-400-bad-request-failures-on-bounce-processing/387431/4 "2025-11-12T23:39:18Z")
What about your outbound email provider? Are you using mailgun or some other transactional email provider?
---
### Author:  [@DevTeVe](https://meta.discourse.org/u/DevTeVe)
#### Post date: [November 13, 2025, 12:29am UTC](https://meta.discourse.org/t/seeing-smtp-should-reject-400-bad-request-failures-on-bounce-processing/387431/5 "2025-11-13T00:29:04Z")
Nope. The same SMTP, outgoing is working perfectly, and incoming for topics it’s also arriving perfectly, the problem is bounces are not visible to the forum so it keeps trying and I get scolded by my hosting provider
---
### Author:  [@tobiaseigen](https://meta.discourse.org/u/tobiaseigen)
#### Post date: [November 13, 2025, 12:46am UTC](https://meta.discourse.org/t/seeing-smtp-should-reject-400-bad-request-failures-on-bounce-processing/387431/6 "2025-11-13T00:46:33Z")
I’m slipping this across to #hosting.
The typical official answer for this sort of thing unfortunately is to say “email is hard”. You will get much better results if you use a transactional email provider.
If you have a budget, you can post in #Marketplace or I can move this topic there for you.
---
### Author:  [@DevTeVe](https://meta.discourse.org/u/DevTeVe)
#### Post date: [November 13, 2025, 12:47am UTC](https://meta.discourse.org/t/seeing-smtp-should-reject-400-bad-request-failures-on-bounce-processing/387431/7 "2025-11-13T00:47:25Z")
Thanks for at least taking the time to look into this with me !!
---
### Author:  [@supermathie](https://meta.discourse.org/u/supermathie)
#### Post date: [November 13, 2025, 10:35pm UTC](https://meta.discourse.org/t/seeing-smtp-should-reject-400-bad-request-failures-on-bounce-processing/387431/14 "2025-11-13T22:35:40Z")
Hi DevTeVe,
I’ve reviewed the code in question and I believe you are right - I think the `smtp_should_reject` code may be incorrectly rejecting bounce messages and replies.
I’m escalating this internally.
In the meanwhile, if you disable the `discourse-smtp-fast-rejection` policy filter does it allow mail to flow?
---
### Author:  [@DevTeVe](https://meta.discourse.org/u/DevTeVe)
#### Post date: [November 13, 2025, 10:37pm UTC](https://meta.discourse.org/t/seeing-smtp-should-reject-400-bad-request-failures-on-bounce-processing/387431/15 "2025-11-13T22:37:30Z")
> [@supermathie](#):
>
> discourse-smtp-fast-rejection
Wow! Thank you for escalating it! I was a little bit hopeless hahaha! I will try disabling `discourse-smtp-fast-rejection` (_although I am not sure how to do that, but I will search and report back_)
---
### Author:  [@supermathie](https://meta.discourse.org/u/supermathie)
#### Post date: [November 13, 2025, 10:39pm UTC](https://meta.discourse.org/t/seeing-smtp-should-reject-400-bad-request-failures-on-bounce-processing/387431/17 "2025-11-13T22:39:26Z")
If you can remove this line from the mail-receiver postfix config file:
```plaintext
smtpd_recipient_restrictions = check_policy_service unix:private/policy
```
This should do the trick - I haven’t tested this but I think it’ll work:
```plaintext
postconf -e "smtpd_recipient_restrictions ="
```
---
### Author:  [@DevTeVe](https://meta.discourse.org/u/DevTeVe)
#### Post date: [November 13, 2025, 10:44pm UTC](https://meta.discourse.org/t/seeing-smtp-should-reject-400-bad-request-failures-on-bounce-processing/387431/18 "2025-11-13T22:44:08Z")
> [@supermathie](#):
>
> `smtpd_recipient_restrictions`
Success!
I am making my `mail-receiver.yaml` like this (_in the meantime or forever? @supermathie_)
```yml
# this is the incoming mail receiver container template
##
## After making changes to this file, you MUST rebuild
## /var/discourse/launcher rebuild mail-receiver
##
## BE *VERY* CAREFUL WHEN EDITING!
## YAML FILES ARE SUPER SUPER SENSITIVE TO MISTAKES IN WHITESPACE OR ALIGNMENT!
## visit http://www.yamllint.com/ to validate this file as needed
base_image: discourse/mail-receiver:release
update_pups: false
expose:
- "25:25" # SMTP
env:
LC_ALL: en_US.UTF-8
LANG: en_US.UTF-8
LANGUAGE: en_US.UTF-8
## Where e-mail to your forum should be sent. In general, it's perfectly fine
## to use the same domain as the forum itself here.
MAIL_DOMAIN: community.example.com
# uncomment these (and the volume below!) to support TLS
POSTCONF_smtpd_tls_key_file: /letsencrypt/community.example.com/community.example.com.key
POSTCONF_smtpd_tls_cert_file: /letsencrypt/community.example.com/community.example.com.crt
POSTCONF_smtpd_tls_security_level: may
POSTCONF_myhostname: community.example.com
POSTCONF_mynetworks: "127.0.0.0/8 [::1]/128 [fe80::]/64 172.17.0.0/16"
POSTCONF_smtpd_recipient_restrictions: ""
## The base URL for this Discourse instance.
## This will be whatever your Discourse site URL is. For example,
## https://discourse.example.com. If you're running a subfolder setup,
## be sure to account for that (ie https://example.com/forum).
DISCOURSE_BASE_URL: 'https://community.example.com'
## The master API key of your Discourse forum. You can get this from
## the "API" tab of your admin panel.
DISCOURSE_API_KEY:
## The username to use for processing incoming e-mail. Unless you have
## renamed the `system` user, you should leave this as-is.
DISCOURSE_API_USERNAME: system
volumes:
- volume:
host: /var/discourse/shared/mail-receiver/postfix-spool
guest: /var/spool/postfix
# uncomment to support TLS
- volume:
host: /var/lib/caddy/.local/share/caddy/certificates/acme-v02.api.letsencrypt.org-directory/
guest: /letsencrypt
```
---
### Author:  [@supermathie](https://meta.discourse.org/u/supermathie)
#### Post date: [November 13, 2025, 11:13pm UTC](https://meta.discourse.org/t/seeing-smtp-should-reject-400-bad-request-failures-on-bounce-processing/387431/19 "2025-11-13T23:13:21Z")
> [@DevTeVe](#):
>
> in the meantime or forever?
Let’s go with “for now” and we’ll update this topic when we have more news.
---
### Author:  [@DevTeVe](https://meta.discourse.org/u/DevTeVe)
#### Post date: [November 13, 2025, 11:14pm UTC](https://meta.discourse.org/t/seeing-smtp-should-reject-400-bad-request-failures-on-bounce-processing/387431/20 "2025-11-13T23:14:00Z")
Thank you very much! I really didn’t expect this to move any further but now it’s perfect and im receiving all the other bounces!
---
### Author:  [@supermathie](https://meta.discourse.org/u/supermathie)
#### Post date: [November 24, 2025, 5:32pm UTC](https://meta.discourse.org/t/seeing-smtp-should-reject-400-bad-request-failures-on-bounce-processing/387431/21 "2025-11-24T17:32:55Z")
follow-up here: [Remove smtp\_should\_reject & discourse-smtp-fast-rejection](https://meta.discourse.org/t/remove-smtp-should-reject-discourse-smtp-fast-rejection/389368)
---
### Author:  [@supermathie](https://meta.discourse.org/u/supermathie)
#### Post date: [November 25, 2025, 5:33pm UTC](https://meta.discourse.org/t/seeing-smtp-should-reject-400-bad-request-failures-on-bounce-processing/387431/22 "2025-11-25T17:33:44Z")
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