Consider this tex file:
\documentclass{amsart}
\usepackage[backref]{hyperref}
\begin{document}
\title{Testing backref}
\maketitle
\section{Introduction}
xxx
\begin{thebibliography}{9}
\bibitem{gCcc}
G. Cz\'edli,
A property.\\
\verb!+arXiv:2112.07594!
\end{thebibliography}
\end{document}
Cannot run it. Why?
GG