Sous vide broken or frozen?

I was cooking 48 hour short ribs at 144 degrees and every thing appeared to be working correctly.  I temperature read 144 degrees and the water was circulating, but when I went to take the short ribs out after 48 hours I discovered the water was cold and my short ribs were ruined.  Does anyone know what happened?  Is this a defect in the machine?  I know the water was the correct temperature after 24 hours because I checked the temp and added hot water into the pan because of evaporation. Can anyone please assist?  Should I contact customer service?

Is it possible you had a power outage? The unit does not reset automatically.

Have you tried heating water without any food to see if it is working properly?.

+1 for john.jcb’s suggestion.  Was the water still circulating when you went to check after 48 hours?  If you check the app, it should have given a reading of 144 for the set temperature and possibly another (much lower) value for the current temperature.  

This is one suggestion a few of us have made for a feature in the app - to record history, so you know when the cook was stopped.

Anytime you’re doing a long cook, you really should be putting the PC on a UPS unit (uninterruptible power supply).  You can get them fairly cheaply at best buy (I like the APC 500’s myself).  

If the PC was still circulating and incorrectly thought that the temperature was 144, despite it being much lower, then yes, you could contact customer support as it appears your unit is defective.