derivatives of vl_nnmax return error: "Expected one output from a curly brace or dot indexing expression, but there were 0 results."

[primasanjaya]

I train the mcnDeepLab and got the error in Max Layer (Max.m) when backprop.

The error comes from function backward(obj, inputs, params, derOutputs);

when running line 17, [derInputs{:}] = vl_nnmax(obj.numInputs, inputs{:}, derOutputs{1}) ;

i got this error message: "Expected one output from a curly brace or dot indexing expression, but there were 0 results."

Any suggestion why?

FYI;

my inputs variable is 1x3 cell(4D single each) size --> [65 65 2 2] for all

params --> 0x0 cell derOutputs --> 1x1 cell and size --> [65,65,2,2]

thank you for any help