Unable to Access WHM After Changing Hostname - Error 521 and Connection Refused

[Helposoft Staff]

The errors you're encountering suggest that there might be network issues preventing your server from connecting to external services, which could be causing the SSL certificate issue and the inability to connect to WHM.

Here are some steps to diagnose and potentially resolve the issue:

1. Check Network Connectivity​

Ensure your server can reach external services:

ping google.com
curl -I https://acme-v02.api.letsencrypt.org/directory

If these commands fail, you have a network issue.

2. Check DNS Resolution​

Ensure your DNS resolution is working properly:

cat /etc/resolv.conf

It should contain valid nameserver entries. You might want to use Google's public DNS for testing:

nameserver 8.8.8.8
nameserver 8.8.4.4

3. Check Firewall Settings​

Ensure that your firewall is not blocking outbound connections:

firewall-cmd --list-all
iptables -L

If necessary, temporarily disable the firewall to test connectivity:

systemctl stop firewalld

4. Check Hostname Configuration​

Ensure that your hostname and /etc/hosts entries are correctly configured. Your /etc/hosts file looks fine, but let's double-check the hostname:

hostnamectl set-hostname hostname.domain.com

5. Restart Network Services​

Restart the network service to ensure all changes take effect:

systemctl restart network

6. Check cPanel and WHM Services​

Make sure cPanel and WHM services are running correctly:

systemctl status cpanel
systemctl status cpsrvd

7. Check SSL Certificates​

Since the SSL certificate renewal failed, you can try to manually install a self-signed certificate or use a valid one if you have it. Here’s how to generate a self-signed certificate:

mkdir -p /etc/ssl/private
openssl req -new -newkey rsa:2048 -days 365 -nodes -x509 -keyout /etc/ssl/private/server.key -out /etc/ssl/private/server.crt

Configure cPanel to use this certificate:

/usr/local/cpanel/bin/checkallsslcerts --force

8. Rebuild cPanel/WHM Configuration​

Force a rebuild of cPanel and WHM configuration:

/usr/local/cpanel/scripts/upcp --force

9. Reboot the Server​

Finally, reboot your server to ensure all changes take effect:

reboot

10. Additional Diagnostic Commands​

Here are a few more commands that can help diagnose the issue:

• Check logs for any additional errors:
  
  

  tail -f /var/log/messages
  tail -f /usr/local/cpanel/logs/error_log

  
  
• Verify that sshd is running and accessible:
  
  

  systemctl status sshd

​

 

[Helposoft Staff]

Encountered issues after changing the hostname on my cPanel/WHM server. Below are the steps I followed and the solution that worked for me:

Issue:

• Changed the hostname to server-host.5ium.com in WHM.
• Cannot access WHM via IP: ERR_CONNECTION_REFUSED.
• Cannot access WHM via hostname: Web server is down Error code 521.

Steps to Resolve:

1. Update /etc/hosts File:Edit the /etc/hosts file to map the server's IP address to the new hostname directly:
   
   

   127.0.0.1   localhost localhost.localdomain localhost4 localhost4.localdomain4
   ::1         localhost localhost.localdomain localhost6 localhost6.localdomain6
   31.172.xx.xxx hostname.domain.com hostname

   
   
2. Rebuild cPanel/WHM Configuration:Run the following commands to rebuild the cPanel/WHM configuration and restart necessary services:
   
   

   /usr/local/cpanel/cpkeyclt
   /scripts/rebuildhttpdconf
   /scripts/updateuserdomains
   systemctl restart cpanel
   systemctl restart httpd
   systemctl restart exim
   systemctl restart dovecot

   
   
3. Verify Firewall Configuration:Ensure that the firewall is not blocking the necessary ports for cPanel/WHM:
   
   

   firewall-cmd --permanent --add-port=2086/tcp
   firewall-cmd --permanent --add-port=2087/tcp
   firewall-cmd --permanent --add-port=2082/tcp
   firewall-cmd --permanent --add-port=2083/tcp
   firewall-cmd --permanent --add-port=2095/tcp
   firewall-cmd --permanent --add-port=2096/tcp
   firewall-cmd --reload

   
   
4. Check Network Configuration:
   • Verify IP address assignment: ip addr show
   • Verify DNS configuration: nslookup server-host.5ium.com
   • Verify routing table: ip route show
5. Check cPanel Ports:Ensure that cPanel ports are open and listening:
   
   

   netstat -tulnp | grep 2087
   netstat -tulnp | grep 2086

   
   
6. Check cPanel Service Status:Ensure all necessary cPanel services are running:
   
   

   systemctl status cpanel
   systemctl status httpd
   systemctl status exim
   systemctl status dovecot

   
   
7. Verify SSL/TLS Configuration:
   • Check SSL certificate: openssl s_client -connect 31.172.80.124:2087 -showcerts
   • Rebuild SSL certificate:
     

     /usr/local/cpanel/bin/checkallsslcerts

8. Reconfigure cPanel:
   • Run initial setup script:
     

     /usr/local/cpanel/scripts/upcp --force

   • Run cPanel check script:
     

     /usr/local/cpanel/scripts/check_cpanel_rpms --fix

9. Inspect cPanel Logs: Check the cPanel logs for detailed error messages:
   
   

   tail -f /usr/local/cpanel/logs/error_log

   
   
10. Reboot the Server:Reboot the server to ensure all changes take effect:
    
    

    reboot

After following these steps, the issue was resolved and I could access WHM without any errors. If you encounter similar issues, these steps might help resolve them.