hi dear forum members,

I am trying to modbus TCP connect MACH3 to STM32F4 uC

these are  the wireshark capture of the TCP traffic and the MACH3 test page

MACH3 connects and gives No error message to STM32

as you can see when I write to 2 holding registers the response from STM32 checksum is correct
however MACH3 gives Receive Timeout

what am I doing wrong , please advise

thank you