3CX have updated their docs and removed help.3cx.com meaning the old documentation for updating SSL certs is now gone, or at least harder to find.

The original URL was https://help.3cx.com/help/en-us/33-installation/148-how-can-i-replace-the-ssl-certificates-for-a-custom-domain. If anyone has a copy of this page, please let me know.

Thankfully updating the SSL certificate is relatively straight forward as the web client runs on nginx.

Updating the SSL Certificate


You will need:

  • Access to the server running 3CX
    • Remote Desktop (Windows)
    • SSH (Linux)
  • The certificate and private key in PEM format

Updating the Certificate

Locate the certificate folder (default):

  • Windows: C:\Program Files\3CX Phone System\Bin\nginx\conf\instance1
  • Linux: /var/lib/3cxpbx/Bin/nginx/conf/Instance1

Copy the certificate and private key into the folder and rename them to <yourdomain>-crt.pem and <yourdomain>-key.pem respectively. EG:

  • mydomain-com-crt.pem
  • mydomain-com-key.pem

Restart Nginx

Restart the nginx service to apply the new certificate.

  • Windows: net stop nginx then net start nginx
  • Linux: systemctl restart nginx