Trouble sending mail via Namecheap Private Email (SMTP) on self-hosted Discourse

Support
1

Hello everyone,

I’ve been trying to configure outbound mail on a self-hosted Discourse installation but so far no luck. Even with Namecheap support involved, we couldn’t get it working. Hoping someone here can point out what I’m missing.

Setup

  • Hosting: DigitalOcean droplet, Discourse installed via the official Docker method (/var/discourse).

  • Domain: Managed via Cloudflare (proxied A records for the site, DNS-only for MX/mail records).

  • Mail provider: Namecheap Private Email.

  • Discourse version: Latest tests-passed branch.

What works

  • I can receive email at my hello@domain.com inbox without issues.

  • MX, SPF, DKIM, and DMARC DNS records are set and validated.

  • Incoming mail via Gmail → hello@domain.com works.

What fails

  • Outgoing (activation emails, test emails from Discourse) never arrive.

  • Namecheap support confirmed my credentials and settings are correct, but couldn’t explain why it fails from the server.

Current app.yml config

DISCOURSE_SMTP_ADDRESS: mail dot privateemail dot com
DISCOURSE_SMTP_PORT: 587
DISCOURSE_SMTP_USER_NAME: hello at domain dot com
DISCOURSE_SMTP_PASSWORD: “PASSWORD”
DISCOURSE_SMTP_ENABLE_START_TLS: true
DISCOURSE_SMTP_DOMAIN: domain dot com
DISCOURSE_NOTIFICATION_EMAIL: hello at domain dot com DISCOURSE_SMTP_AUTHENTICATION: login

I also tried port 465 with:

DISCOURSE_SMTP_PORT: 465
DISCOURSE_SMTP_ENABLE_START_TLS: false
DISCOURSE_SMTP_SSL: true

Debug steps taken

  • Verified DNS records in Cloudflare are correct (MX, SPF, DKIM, DMARC).

  • Confirmed that ports 587 and 465 are not blocked locally by UFW/iptables.

  • Tried forcing IPv4 preference in /etc/gai.conf.

  • Tested with nc and openssl → still timing out.

  • Even Namecheap’s own instructions (587 STARTTLS or 465 SSL) result in failure from the server.

Question

Has anyone successfully configured Namecheap Private Email with Discourse SMTP?

  • Is there a known issue with DigitalOcean droplets reaching mail.privateemail.com on 587/465?

  • Should I give up on Namecheap SMTP and use a transactional mail service (Postmark, Mailgun, SendGrid) instead?

  • Is there a special app.yml flag needed for this provider?

Thanks in advance for any guidance. I’ve hit a wall with this setup.