BRRRR Calculator - Refinance COROI Question

[David Lee Hall, III]

I am new to BP but have found the BP tools beneficial over my traditional Excel approach. One item I have continuously stubbled on though is the Cash-on-Cash ROI for BRRRR Calculator. Whenever I do a prospective deal the calculator comes back at infinity (Inf%) on the Refinance tab. I am trying to figure out if I am leaving out an important metric or if this is a bug in the online software (huge disappointment if so). Anyone have any thoughts/suggestions? If someone even has a deal they have run and did not get this result, if you could provide your inputs so that I can try and compare to what I have been testing with, it would be appreciated.