Overleaf中使用\cite与\bibliography命令报错问题咨询

嘿，今天Overleaf运行异常，我死活搞不定引用（citation）和参考文献（references）功能的报错原因。特意写了一段极简代码测试，但还是出问题，麻烦帮忙排查下我的.tex文件和.bib文件到底哪里有问题～

.tex文件代码 #

\documentclass{article} 
\usepackage[utf8]{inputenc} 
\usepackage{amsmath,amsfonts,amssymb,amsthm} 
\begin{document} 
Einsteins stated the \cite{einstein} 
\bibliography{sample.bib} 
\end{document}

sample.bib文件代码 #

@article{einstein, 
author = "Albert Einstein", 
title = "{Zur Elektrodynamik bewegter K{\"o}rper}. ({German}) [{On} the electrodynamics of moving bodies]", 
journal = "Annalen der Physik", 
volume = "322", 
number = "10", 
pages = "891--921", 
year = "1905", 
DOI = "http://dx.doi.org/10.1002/andp.19053221004", 
keywords = "physics" 
}

内容的提问来源于stack exchange，提问作者Muhammad Usman