Amazon SES + Sendy - duplicated email with different SES IDs

Question

We use Sendy + SES for marketing campaigns. On the 12th of August 2024 we experienced an issue with a campaign: some of our customers received up to 6 duplicated messages.

Here are the headers of two of them (received to one mailbox, I redacted personal info):

Original Message Message ID 0107019147107724-4a83850b-1bdc-4c52-9253-2a7ea106b40d-000000@eu-central-1.amazonses.com Created at: Mon, Aug 12, 2024 at 6:49 PM (Delivered after 0 seconds) From: "(AIT)" <> Using Sendy (https://sendy.co) To: Me Subject: You vs. AI SPF: PASS with IP 69.169.224.6 Learn more DKIM: 'PASS' with domain translation3000.com Learn more DMARC: 'PASS' Learn more

Original Message Message ID 010701914710b8b9-7a1391c2-2495-49ca-8d75-669267c03434-000000@eu-central-1.amazonses.com Created at: Mon, Aug 12, 2024 at 6:49 PM (Delivered after 1 second) From: "(AIT)" <> Using Sendy (https://sendy.co) To: Me Subject: You vs. AI SPF: PASS with IP 69.169.224.1 Learn more DKIM: 'PASS' with domain translation3000.com Learn more DMARC: 'PASS' Learn more

We reviewed SES send logs, and, strangely enough, these duplicated messages do not seem to be reflected in logs.

And here comes the question: if SES assigns an unique ID, does it mean that there was a request to send the message? In other words, who is to blame - Sendy or SES? Are there any means to troubleshoot the situation?

Thanks everyone for help.

Didier_Durand · Accepted Answer

Hi,

Look at this thread: https://sendy.co/forum/discussion/840/end-users-receiving-duplicate-emails#gsc.tab=0

Maybe you are in same situation as one of the answers:

```
Problem found. It was with CRON. Somehow my CRON job got pushed to running 
every minute. Pushed it up to 3 minutes, issue solved. From what I can tell It was 
duplicating the batch that happened to be sent at the very moment the CRON job 
cycled. Those group of users would receive duplicate emails. Why it didn't count against 
SES I haven't a clue.
```

Best,

Didier

Amazon SES + Sendy - duplicated email with different SES IDs

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