There are several potential reasons why a commercial freezer may not be cooling properly, including a malfunctioning thermostat, compressor, or condenser, a refrigerant leak, clogged air filters, or a faulty evaporator fan. A refrigeration technician can diagnose the issue and make the necessary repairs, which may involve replacing components, repairing leaks, or cleaning the system. Regular maintenance and cleaning can help prevent issues with the freezer's cooling system.