Ah, thank you. I apologize for not seeing your post with the attached notebook.
If I open that notebook and evaluate the large cell containing the definition of FoxH and then evaluate your cell trying to use FoxH I get the same result that you do.
In[9]:= FoxH[{{{-2,1}}},{{{0,1}}},-0.5,
OptionsPattern[{FoxHFractionTolerance,FoxHDuplicationLimit,FoxHWorkingPrecision}]]
Out[9]= FoxH[{{{-2,1}}},{{{0,1}}},-0.5,OptionsPattern[{FoxHFractionTolerance,FoxHDuplicationLimit,FoxHWorkingPrecision}]]
When Mathematica returns the expression you just evaluated and does not change it that usually means that Mathematica does not understand how to do that. Many new users are confused when it does this and does not print a message explaining.I am very puzzled by this and spend time trying to find what mistake I might have made. I carefully check spelling and capitalization and {} and find nothing.
I find and read this
https://reference.wolfram.com/mathematica/ref/character/RightArrow.htmland I change the seven "right arrow" unicode characters in the code to the two characters -> which Mathematica will understand as a "Rule" construct.
I read this and look at the examples
http://reference.wolfram.com/mathematica/ref/OptionsPattern.htmlI then try this, also using -> which Mathematica will understand as a "Rule" construct.
FoxH[{{{-2,1}}},{{{0,1}}},-0.5,{FoxHFractionTolerance->0.001,
FoxHDuplicationLimit->50,FoxHWorkingPrecision->$MachinePrecision}]
and it gives a variety of errors, but I suspect those are "good" errors and reflect the very simple example data that you used.
Please make these changes and see if you get the same results. Then try using data which will give a result that you can verify and see if this works.
There are more things about the Options which I think may need further changes, but you should be able to get started using the code.
I believe it is possible, if you wish to use the default values for options, to do this
FoxH[{{{-2, 1}}}, {{{0, 1}}}, -0.5]
