UKULELE Cannot Input TAB notes beyond 4th fret

I am trying to set up a notation and TAB for each Uke string
A string input was fine
E,C,and G strings I have input notation no problem, but when inputting beyond 4th fret in TAB, system will not allow, either entering a 0 or putting 0 on A when trying to enter on E string for example, can anyone tell me how to overcome please.