Invite emails have suddenly stopped working

[simonmc]

Hey everyone,

I’m having a new issue with my Ghost installation on DigitalOcean.

My site has been running fine for years, but recently invite emails stopped sending (using Mailgun) and I get a Request was rejected due to server error.

What I’ve Tried & Observed:

• Created a new droplet (exact mirror) → Invite emails & Ghost work fine there which means my code and setup is fine
• UFW & iptables checked (SMTP shouldn’t be blocked)
• curl https://api.mailgun.net/v3 works**, so outbound connections aren’t entirely blocked
• ghost restart didn’t help
• ghost doctor shows no major issues

Possible Causes?
• Something blocking SMTP (networking issue?)
• Cloudflare interference? (I have ip whitelisted, no events showing blocked)

Has anyone seen something similar? Any ideas on what could be causing this to happen, while a new droplet with the same setup works?

Thanks in advance!

[Cathy_Sarisky]

This is transactional email, so you’ll need to share more about your config. Do you use mailgun for transactional? What’s in your config.production.json (in your ghost install)? Check that you haven’t firewalled that port.

What’s in your logs at mailgun?

[simonmc]

Thanks for your help @Cathy_Sarisky!

I have always used Mailgun for my Ghost setups. I am using the standard setup for the config file:

"mail": {
    "transport": "SMTP",
    "from": "'-----------",
    "options": {
      "service": "Mailgun",
      "auth": {
        "user": "-----------",
        "pass": "-----------"
      }
    }
  },

• This config has been working seamlessly for years without issue.
• This config works perfectly using a Digital Ocean Snapshot droplet with no changes.
• I don’t have any recent Mailgun logs as only stores 5 days worth and it’s been not working for over 7 days now.

The only thing I feel makes sense is that maybe Cloudflare is the problem.

Surely if I can setup a Snapshot and that works, then it’s something external?

I have been playing around with it, but can’t see anything obvious.

[simonmc]

Issue has been resolved. It was a Digital Ocean issue.

This is happening because SMTP has been blocked on your account as of March 6, 2025. This is to make sure that the DigitalOcean servers are not used to send spam emails. Our Security team has reviewed your account and lifted the SMTP port block. You are requested to power cycle the droplet from your end.

To fix the issue, I created a helpdesk ticket requesting to unblock the ports.

I hope this info helps someone else!

[Jinso_Raj]

The same issue happens to me as well (mailgun+digitalocean).
However this is only happening to the newly installed sites. Old ghost sites with same configs and under SAME DROPLET does not have this issue. So not sure if it is a Digitalocean problem or a new ghost version problem

[Cathy_Sarisky]

The resolution is probably the same. Contact digital ocean and ask if they’ve got you blocked.

Update: sorry, you said same droplet! Can you share your config?

[Jinso_Raj]

Thanks for the reply,
I am using this config for the last 1 year without any issues (same digitalocean account, and mail invites in that old websites still works)

"mail": {
  "transport": "SMTP",
  "options": {
    "service": "Mailgun",
    "host": "smtp.mailgun.org",
    "port": "587",
    "secure": false,
    "auth": {
      "user": "abc@xyz.com",
      "pass": "xxxx"
    }
  }
}

But the newly installed ghost instances are not working anymore, so i tried installing a new ghost in one of the old droplet (as a new linux user) and it is also not working, but the old site in the same droplet works well.

[Jinso_Raj]

This is solved by the digital ocean support.

The ports 465 and 587 were blocked on Droplets as of March 6, 2025. Previously, they had already applied restrictions on port 25 also. So creating a ticket solves the problem. Sorry for the trouble.