Problem with communication using CP343 LEAN module in siemens s7-300 PLC

I have been facing problem in establishing communication between two PLCs. I am using Siemens S7-300 PLC and I am using CP343 Lean SIMATIC. NET Module for the communication but it is not happening when the distance is more than 5 meters can someone tellme what maybe the problem and what are the limitations of CP343-Lean communication module.

please help

Patience - patience.

You are probably experiencing the problem when you switch cables, from 5 m to a longer one.
So there is a problem with the longer cable, or the connectors.
Also, try to put a switch between the long cable and the PLC.