G53 (Go to absolute machine coordinates) should be working. In your post, the error has Z5.0 which is either 5mm or 5” above the end of travel for the Z axis depending on which units you are using. This number should always be less than or equal to zero since the Z axis is a negative-going axis. i.e. It travels from 0 to a maximum of -160mm for a OneFinity Foreman.
What are the coordinates you set for the tool setter position in the CONFIG screen?
I was in imperial G20 mode. Your correct, I was assuming the Z position incorrectly. Setting X=12, Y=4, Z=0 leave it at the top position as I wanted. Using Z=-1 causes it to move down 1” for anyone else who makes the same assumption.