Extruder clicking issue with MKS Board v1.5
There is one reason why extruders "click": the material can't be melted and advanced fast enough.

There are two likely reasons why your extruder works when used manually, but not during a print:

1. The temperature is not hot enough for the speed (volume per second) demanded by the print. 

Have you verified that you're using the proper temperature, and that the head is reaching the proper temperature?

2. There is too much resistance on the delivery. 

Have you verified that the Z positioning is not too close, causing back pressure and interfering with the deposition?