Guide CyberPanel Hostname and Mail SSL: Fix the Privacy Error on Port 8090 (Tested)

**JAY** · Today, 06:42 AM

Out of the box, CyberPanel answers on https://YOUR-SERVER-IP:8090 with a self-signed certificate. Every browser shows a "Your connection is not private" page, mail apps warn about the certificate, and clients get nervous. The fix is to give the server a proper hostname with a free Let's Encrypt certificate, for the panel and for the mail server.

We did this on our CyberPanel 3 demo server and checked every port with an outside SSL checker. Two things did not go as the panel suggests:

The recommended setup wizard made the certificate for the website, but the panel on port 8090 still showed a privacy error. The older Hostname SSL page (marked "deprecated") is what actually fixed it.
Mail Server SSL uses one certificate for all domains. Pick the wrong site and every mail app shows a name warning.

Step 1: Pick the right hostname (check your rDNS first)
If you send email from this server, the hostname should match the server's reverse DNS (rDNS, also called the PTR record). Big mail providers like Gmail check it. Look it up from any Linux machine:

Code:

dig -x YOUR-SERVER-IP +short

On our server it returned bm.adminslab.com, so that is the hostname we used. Then make sure the same name has an A record pointing back to your server:

Code:

dig bm.adminslab.com +short

Both must match. If your rDNS shows a generic name from your VPS company (like vps123.provider.net), change it first in your VPS provider's control panel (usually called rDNS or PTR), then come back.

If you use Cloudflare, set this A record to DNS only (grey cloud). Let's Encrypt, port 8090 and mail don't work through the orange-cloud proxy.

Step 2: Run the setup wizard
The Hostname SSL page now says "deprecated in favour of setup-wizard". The wizard lives at:

Code:

https://YOUR-SERVER-IP:8090/base/onboarding

Type the hostname, and leave Skip rDNS/PTR Check unticked if you send mail from this server (tick it only if you don't use email here). Then click Start Configurations.
cyberpanel hostname setup wizard

What it did on our server:

It created a new website for the hostname (bm.adminslab.com shows up under Websites). That is normal: the certificate is issued for that site. Don't delete it later.
It issued a valid Let's Encrypt certificate for https://bm.adminslab.com on the normal port 443.
The progress area stayed empty and the Restart CyberPanel button that the note talks about never appeared, even though the job had finished in the background. Give it a minute or two; you can check that the site appeared under Websites.

But after the panel restarted, https://bm.adminslab.com:8090 still gave a privacy error: the panel itself was still using its old certificate.

Step 3: Install the certificate on the panel (Hostname SSL)
This is the step that fixed it. Go to Security > Hostname SSL, pick your hostname site from the list, and click Issue SSL.
cyberpanel ssl for hostname page

The panel restarts by itself to load the new certificate, so you may see a red "Connection Error, could not connect to server" box for a few seconds. That is expected. Wait 10 to 20 seconds and open:

Code:

https://bm.adminslab.com:8090

(with your own hostname). The privacy warning is gone. An outside SSL checker confirmed a valid Let's Encrypt certificate on port 8090 with the full chain:
cyberpanel port 8090 valid ssl check

From now on, log in to the panel with the hostname instead of the IP. The IP address will keep showing a warning, because certificates are issued for names, not IPs. This is also the address to give mailbox users for webmail: https://bm.adminslab.com:8090/webmail/login.

Step 4: Mail Server SSL (pick the hostname site!)
Go to Security > Mail Server SSL, choose a site and click Issue SSL. You should see "SSL Issued, your mail server now uses Lets Encrypt!".
cyberpanel mail server ssl issued

The catch: Postfix and Dovecot get one certificate for the whole server, made for the site you picked. We first picked our main site cyber.adminslab.com. Port 993 then served a certificate for cyber.adminslab.com only, so a mail app set up with mail.cyber.adminslab.com (the usual setting) gets a name mismatch warning:
cyberpanel mail ssl name mismatch

So pick your hostname site here (bm.adminslab.com in our case). After we did that, port 993 served a valid certificate for bm.adminslab.com. Then set up every mailbox, on every domain, with the hostname as the server:

Incoming (IMAP): bm.adminslab.com, port 993, SSL/TLS
Outgoing (SMTP): bm.adminslab.com, port 587 (STARTTLS) or 465 (SSL/TLS), with the full email address and mailbox password

Your users' email addresses don't change. Only the "server name" in their mail app is the hostname.

If something goes wrong

Let's Encrypt fails: the A record isn't pointing to your server yet, or Cloudflare's orange cloud is on. Fix DNS, wait a few minutes, and try again.
Port 8090 still shows a warning after Step 3: make sure you open the panel by the hostname, not the IP. Then fully reload the page (Ctrl + Shift + R) or try a private window, because browsers remember certificate exceptions you clicked through earlier.
Mail apps still warn: they are probably set to mail.yourdomain.com or the IP. Change the server name to the hostname.
Gmail marks your mail as spam: SSL doesn't fix that. Check rDNS (Step 1) and set up DKIM, SPF and DMARC. See our email setup guide.
Renewal: Let's Encrypt certificates last 90 days. CyberPanel is meant to renew them automatically, but check the panel padlock around day 60 the first time, just to be sure.

More CyberPanel guides

Tested on CyberPanel 3.0 (build 8) with OpenLiteSpeed, Postfix and Dovecot on Ubuntu 24.04, November 2026. Certificates checked from outside with an online SSL checker on ports 443, 8090 and 993.

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