QuickBooks Payroll Error PS077 occurs when the software fails to verify your payroll subscription. This error can arise due to incorrect service keys, outdated billing information, or corrupted data files. To resolve Error PS077, ensure your payroll subscription is active and the service key is entered correctly. Updating your billing information and repairing your QuickBooks installation can also help. Additionally, make sure you are using the latest version of QuickBooks and all payroll updates are installed. For a detailed guide on resolving QuickBooks Payroll Error PS077, visit QuickBooks Payroll Error PS077 Guide.