objective c - Error with UILabel line breaks on iOS -

i have 1 problem. in app using uilabels , autolayout created objective-c code. set number of lines 0.

when have label text on letter(character) longer, label width. when have set line breaks mode word wrap, add dots end. when have set line breaks mode other, add new line last word. didn't resize label.

if text longer, is working correctly.

i can't find reason, causing this. thank answers.