How to debug Mailgun log error (not receiving activation email)

Some users receive the account activation email and others do not. I really don’t know what to look for (this is all Greek to me).

Resending emails (whether initiated by me or the user) does not help, so I’ve had to manually activate some accounts. Users have checked their spam/junk folders.

I am running 1.6.0.beta7+19 on DigitalOcean one-click install, and Discourse is “stock” (no plugins or custom stuff).

The email I use is a Mailgun account used only for the forum (outgoing only).

Here’s one of the (many) errors (I have edited info I guessed was sensitive):

2016-06-06 18:18
“severity”: “permanent”,
“tags”: ,
“storage”: {
“url”: “https:/xxx”,
“key”: “xxx”
“delivery-status”: {
“tls”: false,
“mx-host”: “”,
“code”: 550,
“description”: null,
“session-seconds”: 3.4694018363952637,
“message”: “550 5.1.0 sender rejected”,
“certificate-verified”: false
“recipient-domain”: “”,
“event”: “failed”,
“campaigns”: ,
“reason”: “generic”,
“user-variables”: {},
“flags”: {
“is-routed”: null,
“is-authenticated”: true,
“is-system-test”: false,
“is-test-mode”: false
“log-level”: “error”,
“timestamp”: 1465262290.175899,
“envelope”: {
“transport”: “smtp”,
“sender”: "",
“sending-ip”: “”,
“targets”: “”
“message”: {
“headers”: {
“to”: “”,
“message-id”: "",
“from”: "",
“subject”: “[Single Track British Columbia] Password reset”
“attachments”: ,
“recipients”: [
“size”: 1915
“recipient”: “”,
“id”: “xx”

Here are my Mailgun settings:

  1. Go to admin, email

  2. Send a test email to your email address

  3. Follow the instructions in that email closely. Particularly the mail-tester website part, at the end.

Hello @codinghorror, thanks for the response. Here’s what I see when I send to mail-tester:

Any suggestions?

It says your server is listed in two blacklists, you should resolve that.

1 Like

Spam Cannibal says “bulk emailer not eligible for removal”. Does this mean I have to move from DigitalOcean or Mailgun?

SORBS shows the following:

Summary information for
Note: Times shown are for the latest entry only!
Found 3 network entries and 0 host/domain entries.

Problem Entries, (listings will cause email problems.)
10 “Spam” entries [20:39:16 29 May 2016 GMT+00].
1 “Escalated” entries [02:09:59 21 Mar 2009 GMT+00].

Usage classification (only important if you run your own mailserver.)
Note: Active “exDUHL” entries mean that the IP/Network has been unblocked for some or all IPs from the DUHL.

Problem hostnames/domains (could cause email problems.)
1 “Spamvertised” entries [10:31:33 28 Oct 2015 GMT+00].
Note:These entries are for URLs or email domains, the IPs that may show up as ‘spamvertised’ only indicate where the URL/Host was seen being sent from. Listings for IPs that are ‘spamvertised’ will not usually cause blocking problems unless the email contains the IP address as a URL
Note: For a more detailed view you have to be registered and logged in.

Current Listings (active)
Historical Listings (inactive)
Current Listing with an active exception
Current Listing however, listings of these types can help mail delivery rather than cause blocking.

I do notice that all email notifications I personally receive from the forum go directly to spam, so I’m sure it’s the same way for all forum members. Not sure why this happens considering the forum, domain, and Mailgun address are all very new, and the forum has only a dozen members.

On another note, is there a reason why members that I manually activate still cannot login? This is so frustrating…

It looks like the people formerly using my IP address were chronic spammers, meaning I am on 4 blacklists. I have opened a ticket with Mailgun to request they move my account to a new IP.

I learned a lot about email settings today instead of doing my (real) job. Such is the life of a newbie and totally clueless forum admin…:cold_sweat:

1 Like

I just wanted to update this thread in case someone else here is having the same issue. Mailgun moved my IP to a different one that was not on any blacklists. This mitigated the issue, but the problem persisted for members registering with email addresses hosted by their ISP (for example,,, etc.).

To fully resolve the issue I had to add the following 2 MX records to my DNS settings:

Hostname: mg or
Points To:
Priority: 10

Hostname: mg or
Points To:
Priority: 10