Beckhoff IPC and PLC Communication Error

Recently always have the communication error between Beckhoff ipc and plc, anyone can help, it is setting problem or hadware probelm,many thanks.
PS: once i loaned a ipc and replace the exiting one,working fine.

what is difference?
then we can tell what is wrong as it can now be both.

Existing IPC is P2P, once the network port was broken and sent back to Germany for repair(the whole motherboard was replaced). so loaned a ipc which is nci from supplier, no comunication error when using the loaned ipc.After replacing the repaired ipc, the problem came.
the comunication between ipc and lc is Ethercat, and both are beckhoff products, how comes this error?

by the way, the ipc before the network port was broken and sent back to Germany, got the same problem as well, but not so frequently.so i suspect that the setting problem in beckhoff system manager, but not for sure, how to confirm it?

just found that this communication error is generated by twincat plc control, in the program, it will use the twincat function block which called:FB_EcGetMasterState, when the boolean variable output bit of state is not equal to 0001, it will triger the communication error, so what is 0001 comes from? thanks.

The error code 0001 means ipc internal error, did any one face this problem before? how to solve it. Many many thanks.