This is in hex E2.
See the .h of the ModbusMaster Library what 0xE2 means.
ModbusMaster/src/ModbusMaster.h at master · 4-20ma/ModbusMaster · GitHub
--> your slave is not responding.
start with ONE Master and ONE Slave.
If you like the basic idea of the ModbusMaster, you can try my
[Arduino: Noiasca Modbus Server Library (Modbus Slave)]
(Arduino: Noiasca Modbus Server Library (Modbus Slave))
which shares the concept of callbacks like used in the Modbus Master Library.
There are slave examples which will work with master examples.