cookies and CI4

My God! I had the same problem. I used set_cookie() in version 4, and it did nothing. I loaded the helper() a thousand times, and never got it to work until I came across this post! I read this post several times until I saw setcookie(). The confusion is that these two functions are so similar, and I did not see it right away. Of course, that does not explain why set_cookie() does not work.