Outbound Emails Queued — NXDOMAIN Error and Local DNS Resolution Issue

[mrhakash]

Hello Cloudron Team and Community,

I’m experiencing an issue with outbound email delivery from my Cloudron instance. Emails are consistently stuck in the "Queued for delivery" state, and logs indicate an NXDOMAIN error when attempting to deliver to external domains like Gmail.

Environment Details
Cloudron Version: 8.2.4

OS: Ubuntu 24.04 (DigitalOcean Droplet)

Domain: alphadot.io

Hostname: my.alphadot.io

PTR Record: Set correctly (IP → my.alphadot.io)

DNS: Managed via Cloudflare

Dynamic DNS: Enabled

Port 25: Blocked by DigitalOcean (planning to use SMTP relay)

Observed Behavior
Outgoing emails remain in the queue.

JSON mail logs include:

"host": "NXDOMAIN",
"info": "NXDOMAIN"

dig @127.0.0.1 gmail.com mx returns:

connection refused

Troubleshooting Attempts
Verified unbound.service is active.

/etc/resolv.conf points to 127.0.0.1

Unbound config (/etc/unbound/unbound.conf.d/cloudron-network.conf) includes:

yaml
Copy
Edit
server:
interface: 127.0.0.1
access-control: 127.0.0.0/8 allow
Restarted Unbound and rechecked logs.

ss -tulnp | grep :53 shows nothing listening on 127.0.0.1:53

No firewall is currently applied to the droplet.

Request for Guidance
I’d greatly appreciate help understanding why local DNS resolution isn’t functioning properly in this setup. I’m unsure whether Unbound is misconfigured, failing to bind correctly, or if there's a conflict with systemd-resolved or Cloudron’s internal DNS handling.

Any suggestions or recommended checks would be very helpful. Happy to provide further logs or details if needed.

Thank you in advance.

[joseph]

@mrhakash said in Outbound Emails Queued — NXDOMAIN Error and Local DNS Resolution Issue:

dig @127.0.0.1 gmail.com mx returns:

connection refused

You have to check host -t MX gmail.com 127.0.0.150 . Can you also run cloudron-support --troubleshoot for hints?