WHMCS uses a MySQL® database to store all of your business data, including client and financial records.
For successful installation, updates, and operation, your system must meet the minimum system requirements for your WHMCS version.
Troubleshoot and resolve (S)FTP Backup - Uploading Failed errors.
Troubleshoot and resolve (S)FTP: Unable to open for writing errors.
Troubleshoot and resolve (S)FTP: Unable to write to temp file errors.
Troubleshoot and resolve Argument 1 passed must be an instance of PDOStatement errors.
Troubleshoot and resolve Base table or view not found errors.