This is happening because it is not setup correctly.
- The doser does not need to be connected to the powerbar when you use a dosing pump for ATO. Disconnect it and plug it into a regular outlet.

The PAB-com error is happening because socket 2 which has the doser connected to it is no longer on. The P4 gives this error because communication to the doser is interrupted as a result of the socket no longer being ON.

This is the video you followed? This will show you how to assign the head as an ATO which does not require you to plug it into the powerbar.