MessageBox don't like c# \n or ' I dont know

Who knows why this line doesn't work. It passes over it and no message appear. But if I put a simple line of text without any \n or ' it works

SBOApp.MessageBox("Did you check...\n\n(1) Client's name\n(2) Bill-To address\n(3) Ship-To address\n(4) Shipping Type\n\n", 1, "Ok", "", "");