编译时出现数字??

Question

我正在尝试在内容中添加对图像的引用。编译后的输出显示了图像，但文本中对图形的引用如下如图 ？？代码的 MWE 如下所示

\documentclass[a4paper,fleqn,usenatbib]{mnras}
\usepackage{mathptmx}
\usepackage[T1]{fontenc}
\usepackage{ae,aecompl}
\usepackage{graphicx}   % Including figure files
\usepackage{amsmath}    % Advanced maths commands
\usepackage{amssymb}    % Extra maths symbols
\usepackage{wasysym}
\usepackage{xcolor}
\usepackage{textcomp}
\usepackage{xcolor,pict2e}% to allow any radius
\usepackage{mathtools}
\usepackage{tikz}
\definecolor{turquoise}{rgb}{0.19, 0.84, 0.78}
\usepackage[lofdepth,lotdepth]{subfig}
\usepackage{multirow}
\usepackage{amssymb}    % Extra maths symbols
\usepackage{wasysym}
\usepackage[para]{threeparttable}
\definecolor{turquoise}{rgb}{0.19, 0.84, 0.78}
\usepackage{float}
\usepackage{csquotes}
\usepackage{setspace}
\openup 1em
\setstretch{2.25}
\usepackage{cleveref}
\author{AB}
\title{lil}


\begin{document}
\label{firstpage}
\pagerange{\pageref{firstpage}--\pageref{lastpage}}
\maketitle

It without lesser fish very waters day midst creepeth you likeness light moved kind evening. Man them shall created make whose upon abundantly. Great whales Won't. Be first doesn't be which grass you appear. Saw sixth whose. Fruitful isn't image greater i make morning cattle fill fish replenish is, that.
The image displayed is \ref{fig:841}


\begin{figure}
    \centering
        \includegraphics[scale=0.25]{841.pdf}
        \caption{Units on y axis are of the order of $10^{-14}$ erg/sec/cm$^{2}$/\AA as a function of Date. The values are at the midpoints of the error bars ($\pm 1 \sigma$).}
    \label{fig:841}
\end{figure}

\bsp    % typesetting comment
\label{lastpage}
\end{document}

% End of mnras_template.tex

注意：除了模板文件中已有的默认包之外，我没有为本文添加任何包。