There are a few potential causes of an RV refrigerator stopping cooling. One possibility is that the fridge is not level, which can prevent proper airflow and cause the compressor to overheat. Another issue could be a dirty condenser coil, which will reduce the fridge's ability to dissipate heat. Additionally, if the door seals are damaged or not sealing properly, warm air can enter the fridge and cause the contents to spoil. Finally, a faulty thermostat can also cause cooling problems. If you're experiencing cooling issues with your RV fridge, it's best to consult with a certified technician to diagnose and resolve the problem.