Troubleshooting Licensing
If you encounter errors or issues while authenticating with WHMCS, see the sections below to start troubleshooting and resolve the issue.
For general steps to troubleshoot problems in WHMCS, see Start Troubleshooting.
Licensing Errors
You may encounter the following common issues:
| Error or Issue | Cause | Next Steps |
Curl Error - Couldn't connect to host (7) or Server Command Error - Curl Error - Couldn't connect to host (7) or Curl Error: Connection refused - Code 7 | Your firewall is blocking a necessary port or your IP address is not whitelisted. | cURL Couldn't Connect to Host Errors |
Curl Error - Couldn't resolve host (6) or Server Command Error - Curl Error - Couldn't resolve host (6) | Your firewall is blocking a necessary port. | cURL Couldn't Resolve Host Errors |
Your license key is invalid | You performed a required license check from a non-web context. | Invalid License API Errors |
License Invalid | You entered an invalid license key or moved the WHMCS installation without updating the license. | Invalid License Errors |
Invalid License (on HostGator) | HostGator made mass changes to one or more directories. | Invalid Licenses on HostGator |
A license key is required. If you don't have one, please visit www.whmcs.com to purchase one. | There is an issue with the PHP sessions configuration in your server environment. | License Key Required Errors |
No Connection | There is a problem preventing your server from communicating with the WHMCS licensing server. | No Connection Errors |
| You see SSL-related error messages while attempting to connect to the WHMCS licensing server. | Your CA bundle files are missing or out of date. | Outdated root CA Bundles |
Control Panel Licensing and the cPanel Licensing Addon
- For help troubleshooting issues with the cPanel Licensing Addon, see Troubleshooting Addon Modules.
- For help troubleshooting licensing issues with hosting control panels, see Troubleshooting Server Issues.
Last modified: 2025 May 7