Check the seal on top of the keg for damage. There is a quick fix for a damaged seal. Acquire a washer from the back of a faucet and center on top of the seal. Tap over this with the coupler and hopefully the seal has been repaired temporarily.
This time of the year is tough on kegs. Extreme temperatures can damage the internal components as well as change conditions of the product. Hopefully this is not what you are encountering Topgun. Maybe the Beer God is angry!
Scott Zuhse, Instructor
Micro Matic Dispense Institute