Modbus tcp errors

My logs are full of these messages, but I cant figure out which device is causing it. How can I find out which devices are causing these errors?

INFO | jvm 2 | 2018/12/11 11:18:55 | E [d.M.ReadInputRegistersRequest ] [17:18:55]: Uncaught Throwable handling response. key=java.lang.Object@213e45dd, req=[ ], rsp=[ 00 01 01 00 50 74 ]
INFO | jvm 2 | 2018/12/11 11:18:55 | java.lang.ArrayIndexOutOfBoundsException: null
INFO | jvm 2 | 2018/12/11 11:18:56 | E [d.M.ReadInputRegistersRequest ] [17:18:56]: Uncaught Throwable handling response. key=java.lang.Object@213e45dd, req=[ ], rsp=[ 00 04 B4 00 2B 00 00 00 2C 00 2B 00 00 00 00 00 00 00 00 01 67 9D 09 73 9F 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 40 67 7F 0C 40 60 9E 43 5D 46 21 62 00 00 00 00 00 00 00 00 00 0B 00 1F 42 C7 B7 38 00 17 00 3B 42 C7 FE D1 46 2A 4D 6D 42 A5 E5 3F 46 BC 15 C6 46 04 CB 4D 46 BB EF 9E 46 03 DF BC 43 01 56 13 43 01 40 AB 42 C3 84 AA 60 7C ]
INFO | jvm 2 | 2018/12/11 11:18:56 | java.lang.ArrayIndexOutOfBoundsException: null