Troubleshooting

Most setup issues come down to DNS, the cloud firewall, or the outbound-port-25 block. Here's how to recognize and fix each.

The panel won't open at my domain

• http://server-IP/ works but the domain doesn't — DNS isn't resolving yet. Check panel.yourdomain.com at dnschecker.org (type A). If it's blank, your DNS records or nameservers aren't set — see Point your domain.
• The domain has no nameservers at all — the registrar delegation isn't published, or you set records at a DNS host that isn't authoritative. Verify NS at dnschecker.org (type NS); if it's empty or wrong, fix the nameservers at your registrar, or move to Cloudflare.
• Nameservers point somewhere, but it still won't resolve ("REFUSED") — the DNS host isn't actually serving the zone. Activate DNS management there, or move the domain to Cloudflare (it always serves the zone once added).

HTTPS isn't active (padlock missing)

HTTPS switches on automatically within ~5 minutes once panel.yourdomain.com points at the server. If it hasn't:

• Confirm the A record resolves to the right IP (dnschecker.org).
• Make sure ports 80 and 443 are open in your cloud firewall.
• If you use Cloudflare, set the panel record to DNS only (grey cloud), not proxied.
• To force it now: SSH in as root and run sudo nimbopanel-enable-https.

Customers can't send email / outgoing mail bounces or times out

Almost always the provider's outbound port 25 block. Set up an SMTP relay on port 587 — see Email deliverability & sending. A working relay shows status=sent in the mail log.

Email sends, but lands in spam

The message isn't fully authenticated. Check that all three are published and passing for the sending domain:

• SPF includes your relay (e.g. include:spf.brevo.com).
• DKIM — the domain is verified in your relay and its DKIM records are in your DNS.
• DMARC — a v=DMARC1; p=none; … record exists (Nimbopanel adds one per domain).

Incoming email never arrives

• Confirm the MX record for the domain points at mail.yourdomain.com and that mail.yourdomain.com resolves to your server.
• Make sure inbound port 25 is open in your cloud firewall (inbound 25 is almost never blocked — only outbound is).

A tool page (webmail, phpMyAdmin) shows an error or won't load

• phpMyAdmin returns 401 without a panel session — that's expected; open it from inside the panel (single sign-on).
• Webmail / a site returns 502 — a PHP service may have restarted. Check services with systemctl status. If it persists after a moment, re-run the updater (sudo nimbopanel update) to re-apply the managed config.

Where to look

• Panel + service logs live in the systemd journal: journalctl -u nimbopanel -n 50.
• Mail delivery results: journalctl -t postfix/smtp --since -10min (look for status=sent / status=bounced).
• The install log is at /var/log/nimbopanel-install.log.

Still stuck? Note the exact symptom and the relevant log line — that's usually enough to pinpoint it fast.