WebControl chain length warning during initial setup

I am getting the following warning scroll on the screen after doing the quick configuration, set sprockets to vertical and extending the chains on m 12 ft frame.

Message: Unable to find valid machine position for chain lengths 0.00, 0.00 Left Chain Length Greater than System Settings Chain Length LeftChainLength: 4104.43 System Chain Length: 3960

The 3960 mm chains I currently have appear long enough to service the entire work area,

My top beam length is 3630.6 mm, vertical motor height is 769 mm. Should I move on the calibration step, or do I need to change a parameter, first?