Shared bibliography

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 abstractnamevspace{-.5em}vspace{0pt}
    end{center}
    list{}{%
        setlength{leftmargin}{0mm}% <---------- CHANGE HERE
        setlength{rightmargin}{leftmargin}%
    }%
    itemrelax}
{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