Cash flow vs 50% rule

[Ginger Vaadi]

Hi there. So I have a property that according to the bigger pockets calculators will cash flow $100+ per month but the 50% rule is -901. My question is what do I do with this information. Why is the 50% rule so negative while the cash flow is positive? I need this explained in layman's terms please I am still learning and the math breaks my brain a little, haha. Thanks in advance