The rat may not have been warm enough. I submerge mine in hot water for 10-15 min depending on the size of the rodent. For rat pups I do 10 min. You want it to be the same temp as a live rat. Sometimes mine refuse if the rat isn't warm enough. And then sometimes snakes refuse feeds. If your temps are right, the rat is warm enough and everything else is fine you can chalk it up to typical ball python feeding behavior. I have one that will refuse 3 out of 4 meals. I refreeze a thawed rat once. If it's refused again I throw it away. Give him a week and then try again.