Following the update to version 2026.1.5, Dannii reported a new site advisory requiring the configuration of aws_sns_topic_arn_allowlist for servers using Amazon SES for email. The setting aims to secure bounce notification processing, but initial documentation lacked clear instructions. Jonathan5 resolved the warning by locating existing SNS topics for bounces and complaints in the AWS console and adding their ARNs to the Discourse setting, noting that this silenced the alert.
jeff_y questioned whether the warning applies to setups that use SES only for sending mail while handling incoming bounces via a separate tool like mail-receiver. Dannii expressed frustration over the lack of explanation but noted that ignoring the warning had no visible negative impact. nat clarified the situation, confirming that the warning appears broadly if the SMTP hostname resembles SES, even if SNS is not actively used for bounce delivery. For users relying on mail-receiver for bounces, the setting can remain empty.
Nat further specified that Discourse currently processes only bounces via this webhook, meaning adding a complaint topic ARN (as Jonathan5 did) does not enable complaint handling. In response to user feedback, the Discourse team has updated the descriptions and warnings to clarify when the setting is required and when it can be safely ignored.
Since updating to 2026.1.5, I now see this site advice:
The server is configured to send emails via Amazon SES but you haven’t allowlisted any SNS topic ARNs. Bounce notifications will be rejected until you add the legitimate ARN to aws_sns_topic_arn_allowlist.
I can’t find any information about this setting though.
On the Amazon SNS console I already had two “Topics” set up. I have only hazy memories of setting up SES. It must have been in the relevant Discourse instructions. It’s also mentioned in this recent topic: How do I properly configure the AWS SNS topic ARN allowlist?.
One was for bounces and one for complaints, and there were ARNs for each in the format arn:aws:sns:eu-west-1:111111111111:DiscourseBounces. I put both of these ARNs into the aws_sns_topic_arn_allowlist Discourse setting and the warning doesn’t appear any more. I hope that means I did the right thing…
According to this, it sounds like the setting is for Discourse learning about bounces that were received by Amazon after sending via SES.
However, I’m using SES just to send messages for forum.example.com, and I’m using mail-receiver to receive replies and bounces. I think the warning message in the Discourse dashboard only applies to people receiving replies & bounces via SES, right? Not for those with an MX record going to our own server?
Ah thanks for the topic, this had eluded me. We should have explained when this setting applies and where to find the value, and the warning is too broad.
It appears whenever the SMTP hostname looks like SES and the allowlist is empty, even if SNS isn’t part of your setup.
If SES bounce feedback is reaching Discourse through mail-receiver, you don’t need to populate this setting. You can leave it empty.
@Jonathan5, the bounce topic ARN you added is the right value. Though, small note - Discourse currently only processes bounces through this webhook, so adding the complaint topic doesn’t enable complaint handling.