BCH Share rejected: duplicate share
[2023-01-31 15:11:53.1691] [I] [bch] [0HMO3GG3818JP] Share rejected: duplicate share [Antminer BHB42XXX/Tue Mar 22 11:52:15 CST 2022]

config
            "ports": {
                "8888": {
                    "listenAddress": "0.0.0.0",
                    "difficulty": 30000.0,
                    "tls": false,
                    "tlsPfxFile": "/var/lib/certs/mycert.pfx",
                    "multiplyDifficulty": true,
                    "varDiff": {
                        "minDiff": 30000.0,
                        "maxDiff": 300000.0,
                        "targetTime": 15,
                        "retargetTime": 90,
                        "variancePercent": 30,
                        "maxDelta": 500
                    }

Hi! How to fix it?