750-362 Modbus Coupler Outputs ON/OFF repeatedly

We are using Codesys 3.5 on a 750-8212 and working with remote IO on a 750-362.
I can force the 750-515 output the output will turn on but immediately turns off and on.
What am I missing?

Check if there is no overlapping of %Q.
Also, if the alternative watchdog is enabled on the coupler, make sure the communication request interval is lower than the watchdog value.
The principle of alternative watchdog is to disable outputs when there is a connection timeout.