I am unaware of what could make \href fail so I will place here my code together with all packages used. I've seen in the past packages intercept one another.
I am trying to produce a link to a paper like this:
\documentclass[12pt, a4paper, draft]{book} % Packages \usepackage{hyperref} \begin{document} [\href{https://pos.sissa.it/397/174/}{doi: 10.22323/1.397.0174}] \end{document} However the output is not clickable in my PDF: 
I can use \href in my CV just fine, which is of course another document class. Has anybody seen this before?