Relay power up crashes system

I have an 8 channel relay out at my pool that works fine manually by pushing buttons on the relay and off to control loads BUT each time it's power supply/circuit breaker is turned on it crashes the rest of my cbus network.

All light switches then stop working and blink if touched leaving lighting in its then current state.

To make it more confusing, cbus toolkit cannot connect to the network whether that relay is powered up or not so am not sure how to diagnose what is occurring.

 

Ok,
1 Do you have a color touch screen, if so it can couse toolkit to fail if the transmit part is faulty
2 Is it a new relay, if it is try turning off the power supply in it if you can
3 If its an old one chek the cbus voltage across the + - cables... 24 to 31 volts is ok
And check the + and - to earth ground... they must match either problem voltage means replace the relay