# Chemmacros: Undefined control sequence. \end

When I try to create a reaction from chemmacros/reactions I got the following error. I dunno what I am missing. Please help. Thank you.

line 11: Undefined control sequence. \end
line 11: Missing number, treated as zero. \end
line 11: Missing number, treated as zero. \end

Minimum Working Example

\documentclass[12pt,a4paper]{article}
\usepackage{chemmacros}
\chemsetup{modules={reactions}}
\begin{document}
\begin{reaction}
A + B -> C
\end{reaction}
\end{document}