Shared bibliography

Question

I am trying to use the same .bib file for different versions of my paper, but when I use different versions of the original .tex file the bibliography stops working (it works only with the original).

This below is the code before the beginning of the document:

\documentclass[a4paper,12pt]{article}
\usepackage{natbib}
\usepackage{caption}
\captionsetup{font=footnotesize}
\usepackage{color}
\usepackage{graphicx}
\usepackage[fleqn]{mathtools}
\setlength{\parindent}{0em}
\usepackage{enumitem}
\setlength{\parskip}{0.5em}
\usepackage{subcaption} 
\usepackage{float}
\usepackage[utf8]{inputenc}
\usepackage{fancyhdr}
\pagestyle{fancy}
\fancyhf{}
\cfoot{\thepage}
\lhead{Student ID:10384157}
\usepackage{setspace}
\doublespacing
\usepackage[bottom]{footmisc}
\renewcommand{\arraystretch}{1.5}
\usepackage{adjustbox}
\usepackage{geometry}
\geometry{margin=3cm}
\usepackage{dirtytalk}

\renewenvironment{abstract}
{\small
    \begin{center}
        \bfseries \abstractname\vspace{-.5em}\vspace{0pt}
    \end{center}
    \list{}{%
        \setlength{\leftmargin}{0mm}% <---------- CHANGE HERE
        \setlength{\rightmargin}{\leftmargin}%
    }%
    \item\relax}
{\endlist}

\title{}
\author{}

and this is how I call the bibliography within the file:

\bibliographystyle{apa} 
\bibliography{BiblioC1}

What am I missing? Thanks for your help! Manuel