I have a self hosted Ghost install (actually three of them) on a Digital Ocean droplet. About 6 weeks ago, I stopped seeing the notifications for comments left, as they were being flagged by my mail provider, Proton Mail, as possibly spoofed.
The site is https://sweatyspice.com
I am using Mailgun for email delivery. domain is mg.sweatyspice.com
It is at 6.10.3 (I do keep it updated).
When I publish, the email lands in my inbox fine. It is just the notifications for comments left that get shunted to the Proton Mail spam folder (took me a while to realize that no, people hadn’t stopped commenting, d’oh!)
This is the warning I get: This email has failed its domain’s authentication requirements. It may be spoofed or improperly forwarded.
Internet searches hasn’t given me anything useful, apart from Proton Mail being paranoid about everything (which is why I use it…)
Any thoughts or help?
jannis
December 26, 2025, 4:57pm
2
Haven’t used Proton in a while, but can you see the reason it was flagged?
Take a look at the headers of the flagged email and check whether SPF, DKIM, or DMARC pass (you can paste the headers into here, for example: Email Header Analyzer, RFC822 Parser - MxToolbox )
This is what I get:
All the DNS setting in Mailgun are confirmed and clear.
Here are the full headers:
Return-Path: bounce+5ef8ce.e2e4be-geoffand=pm.me@mg.sweatyspice.com geoffand@pm.me geoffand@pm.me header.d=mg.sweatyspice.com header.a=rsa-sha256
header.from=sweatyspice.com
Authentication-Results: mail.protonmail.ch; spf=pass smtp.mailfrom=mg.sweatyspice.com header.d=mg.sweatyspice.com header.i=@mg.sweatyspice.com header.b=“jPVZQ5fK”m43-7.mailgun.net (m43-7.mailgun.net [69.72.43.7]) (using TLSv1.2 withgeoffand@pm.me ;d=mg.sweatyspice.com ; q=dns/txt;geoff@sweatyspice.com geoff@sweatyspice.com geoffand@pm.me ba142db8-1bff-febd-dfdd-34317919f1e7@sweatyspice.com
-----BEGIN PGP MESSAGE-----
wcBMA4WlUUFHbVQTAQgAuNED3tYezC6btgire2rau81YaFjc/G6bmgMfOLgy
jannis
December 26, 2025, 6:39pm
4
SPF, DKIM, and DMARC look fine. The “DKIM Authenticated” being crossed out is also okay, since the signature has an expiration timestamp that’s in the past (with the email being from 28 November).
The email you have posted here was apparently sorted into your normal inbox though, not into spam. It does have an elevated spam score.
Other than that, the headers look fine – so this might be an internal Proton thing.
Has anyone else reported this issue from another provider?
It might also be worth reaching out to Proton. When I hosted my emails with them they were pretty helpful.
I’ve opened a ticket with them too. I did a search here and found nothing (at least in the last couple of years).
That email did get shunted to the Spam folder though.
jannis
December 26, 2025, 6:50pm
6
I don’t see this as a Ghost issue, but probably an issue with Proton’s internal sorting. So, a ticket on their side is probably best.
Got it. Then their headers are a bit weird
1 Like
Ok, I feel like an idiot.
I figured it out. I had configured the transactional emails in the config.production.json file for my mailgun info, but I left the “transport” as “Direct” not “SMTP”, and once I fixed that, all is good.
I pulled a total Homer…
1 Like
