I am using the TA514 Safety Training case, the error messages I receive is PROFIsafe communication error.

Hi I am using the TA514 Safety Training case, which consists of the AC500 Safety PLC's. I succcesfully load the Training project by ABB however, it gives me a PROFIsafe communication error. The ZP ERR 1 and ZP ERR 2 lights are toggling ON/OFF on the DX581-S and DI581-S modules, I can read analogue values but no outputs are working? Any help or resources would be appreciated.