One question about goodness_of_fit

Hello , Everyone. I am really confused why I got totally different results by the commands as:
stats.goodness_of_fit(stats.lognorm, data, fit_params= {‘loc’:0},statistic=‘ad’, n_mc_samples=9999,)
stats.goodness_of_fit(stats.lognorm, data, known_params= {‘loc’:0},statistic=‘ad’, n_mc_samples=9999,)