Communication error with delta hmi and s7-300

One of the machines i reprogrammed a while ago started giving me communication error 14 on hmi. Sadly i could find about the error is the station number of plc is exceeding the limit.
Anyone experienced such problem or any ideas what exactly exceeds what limit, data,memory,communication etc?
It was a working machine so i doubt it is program based. The error isnt constant, it only occurs when i start 2 of the 5 motors which are driven by Vfd. Analog outputs are used for frequency setting and analog inputs are used to monitor currents of motors.
When the error pops up screen freezes and cant do anything until i stop the monitors with emergency stop.

What type of communications is the setup using? Are you talking to a plc, the vfd, multiple vfds?

If that error involves station numbers then it could be something in your communication settings. I believe if a numeric display tries to read a value that is larger than what it is set up to handle it just reads out #### and won't cause any error codes. All of the errors I've had with the Delta screens are from communication settings or missing tags.

Communication is mpi. Only hmi and plc is in that. I have 3 vfds, 2 5.5kw and one 1kw. Small one works fine other 2 causing error.
Vfds are abb, i tried the changing those to local control and started manually with pad buttons instead of plc, disconnect regarding analog inputs and outputs, remove them from plc program but error still pop ups, so i m guessing its some kind of noise issue. Gonna try replacing the communication cable