"cryptonight" should be "cryptonight/2", someting like the following line:
"algo": "cryptonight/2",
drivel...
But i think there in algo option need to stay something else, not just cryptonight :/
judging by your configuration, you see it for the first time. And exactly what you and leonsnow there think is indicated elsewhere "variant": 2, as I wrote earlier.
For xmrig miner, I use "cryptonight/2". If it is another miner, I do not know.