General errors can occur in many places throughout WHMCS, and can be due to many different problems. However, fixing them is often simple.
Troubleshoot and resolve 404 Not Found: The requested URL was not found on this server. errors.
Troubleshoot and resolve You are attempting to access the admin area via a directory that is not configured. errors.
Troubleshoot and resolve a blank Admin Dashboard after an update.
Troubleshoot and resolve blank or partially-rendered pages after an update.
Troubleshoot and resolve incorrect display of accented (Unicode) characters.
Troubleshoot and resolve The file is corrupted. errors.
Troubleshoot and resolve Curl Error - Couldn't connect to host (7) errors.
Troubleshoot and resolve Curl Error - Couldn't resolve host (6) errors.
Troubleshoot and resolve Curl Error - 28 connect() timed out errors.
Troubleshoot and resolve InvalidArgumentException: Query string must not include a URI fragment errors.
Troubleshoot and resolve Down for Maintenance errors.
Troubleshoot and resolve duplicate system themes appearing in the System Theme menu.
Troubleshoot and resolve empty pages while using WHMCS.
Troubleshoot and resolve main(): Failed opening required '/path/to/whmcs/..filename.php' errors.
Troubleshoot and resolve The file cannot be decoded errors.
Troubleshoot and resolve File Not Found errors.
Troubleshoot and resolve Impossible to create the root directory errors.
Troubleshoot and resolve Fatal error: The file was encoded by... errors.
Troubleshoot and resolve Site error: the ionCube PHP Loader needs to be installed. errors.