Modbus TCP connect Telnet CRC Error

[danhloimta]

I am using modbus tcp connect type Telnet and using HW Tool as an intermediary to connect the app and Modbus Slave.

APP -> HW -> Modbus Slave

HW tool: https://www.hw-group.com/software/hw-vsp3-virtual-serial-port

HW

Modbus Slave

When I enter the value 32767 (Max value) in Short, the library returns an error. (32766 is ok)

Data Long/Word/Dword also has the same error (in the range approaching the max value, the library returns an error)

I guess it might be because the intermediate HW tool in the middle is converting incorrectly and transmitting it to the app, but I tried another HW replacement tool, Serial to ethernet connector, which also had the same error.
Serial To Ethernet connector: https://www.serial-over-ethernet.com/downloads/post-download.html

I read it and saw the error return code here. Can anyone explain why such an error occurs?