Profibus struggles

Hello, I am an industrial mechanic and have been having occasional profibus faults for weeks now where the nodes on the network fault solid red.

Not getting a good alarm description on the machine. Open the cabinet to the profibus network faulted. We saw around 4 volts green signal on profitrace. We installed a repeater and now have 5 volts across the board.

Machine is still shutting down and needed plc to be reset in order to reset the profibus network.

After installing repeater the fault frequency seems unchanged. This was a decent install where we had to add termination resistors and make pb cables.

Any profibus trouble shooting experts here?