Mails are being sent over and over again from campaign

Your software
My Mautic version is: 2.16.2
My PHP version is:

Your problem
My problem is:
Hi All, i have a campaign that is supposed to send an email to a contact every 30 days. The condintons are as follows- the campaign is segment based, after the contact starts the campaign he waits 2 days before being sent an email. after 30 days he is removed from the campaign segment and restarts the campaign. This campaign worked for the last couple of months but recently several contacts got the emails over and over again in the same day. Does anyone have any idea why this could happen?
These errors are showing in the log:
No log errors
Steps I have tried to fix the problem:

Hey Omer - I’m getting the same exact issue. Same Mautic version too. I don’t know what is causing it and if anyone has any insight, that would be so appreciated! I’ve had to disable mautic because of every one of my users getting duplicate emails.

Some additional details regarding the duplicate emails being sent

  • Users are being sent duplicate emails, often in the same day from the same campaign
  • In the Mautic contact section for a user, Mautic shows that there is just one email being sent to the user; i.e. the duplicate email isn’t shown in the Contact History page
  • The unsubscribe links do not match in the duplicate emails - I find this really weird; in the first email, the unsubscribe link is correct and when clicked on, takes you to the unsubscribe confirmation page; in the duplicate email, the unsubscribe link is incorrect, and when you click on it, it takes you to a “Record not found.” page

Would really appreciate if anyone had any insight into what could be causing this? As with Omer, it was working perfectly fine before but seems like this has just happened recently.

Could be related to this issue, what mail transport are you using to send your emails?

Hi! Thanks for getting back to me so quickly - I’m using the ‘Other SMTP Server’ option, and have set it up to integrate with Postmark, like below:

My use case is Transactional emails, not marketing emails.

It could be possible that link you provided could be a fix, though I’m not too sure if I understand. If I understand correctly, it’s possible that Mautic fails for some reason and keeps no log of the failed emails? What would cause Mautic to fail? Would appreciate your input here, thanks a mil!