Error: There were undefined references

I am having trouble in generating bibliography. I am using Mendeley for generating .bib file. Before I was using the same process it was working very accurately but now its not. Whenever I try to compile my document it is continuously saying there were undefined references although I am putting it in citation very well by using citep{}. under text its working properly but at the end no bibliography is generating. The code I am using is given below

documentclass[a4paper,twoside,openright,12pt]{book}

usepackage[T1]{fontenc}

usepackage{newtxtext}

usepackage[utf8]{inputenc}

usepackage[english]{babel}

usepackage{csquotes}

usepackage{amsthm}

usepackage{amsmath}

usepackage{mathptmx}

usepackage{mathrsfs}

usepackage{textcomp}

usepackage{textgreek}
 
usepackage{float}
restylefloat{table}


usepackage{url}
 
usepackage[natbib=true, backend=biber,style=apa]{biblatex}

addbibresource{library.bib}

 
usepackage[final]{graphicx}

graphicspath{{Figures/}}


usepackage{geometry}
geometry{verbose,tmargin=1cm,bmargin=1cm,lmargin=1cm,rmargin=1cm,headheight=0cm,headsep=0cm,footskip=0cm,
    nomarginpar % <-- comment out this option to see the difference
} 
pagestyle{empty}
setlength{parskip}{0bp}
setlength{parindent}{0pt}
usepackage{marginnote}
usepackage{parskip}
usepackage{setspace}
doublespacing

usepackage{caption}% <-- added


usepackage{subcaption} 
usepackage{tabulary}
usepackage[para]{threeparttable}
usepackage{array,longtable,tabularx}
usepackage{booktabs,ragged2e,ltxtable,pdflscape,filecontents}

usepackage[flushleft, online]{threeparttablex}
usepackage{ltablex}% 
usepackage{booktabs,ragged2e,ltxtable,pdflscape,filecontents}
newcolumntype{L}{>{raggedrightarraybackslash}X}%
usepackage{siunitx}% <-- added

%for creating hyperref. 
usepackage{hyperref}
hypersetup{
    colorlinks=true,
    linkcolor=black,
    filecolor=black,
    citecolor = black,      
    urlcolor=blue,
}

usepackage{acro}
acsetup{list-style=longtable}




begin{document}

author{XYZ}
title{ABC}
date{July 2020}

frontmatter
maketitle

tableofcontents
listoftables
listoffigures

mainmatter
include{./Chapters/Chapter1}
include{./Chapters/Chapter2}

backmatter
% bibliography, glossary and index would go here.

printbibliography
end{document}

Plz help me I am in real trouble. Here is a .blg file

[0] Config.pm:304> INFO - This is Biber 2.14

[0] Config.pm:307> INFO - Logfile is 'Chal jaa bass.blg'

[139] biber-MSWIN64:322> INFO - === 

[202] Biber.pm:415> INFO - Reading 'Chal jaa bass.bcf'

[489] Biber.pm:943> INFO - Found 1 citekeys in bib section 0

[525] Biber.pm:4256> INFO - Processing section 0

[525] Utils.pm:75> INFO - Globbing data source 'library.bib'

[542] Utils.pm:91> INFO - Globbed data source 'library.bib' to library.bib

[574] Biber.pm:4455> INFO - Looking for bibtex format file 'library.bib' for section 0

[622] bibtex.pm:1653> INFO - LaTeX decoding ...

[2055] bibtex.pm:1471> INFO - Found BibTeX data source 'library.bib'

[2058] Utils.pm:304> WARN - Duplicate entry key: 'Hasan2011' in file 'library.bib', skipping ...

[2146] Utils.pm:304> WARN - BibTeX subsystem: C:UsersAhmedAppDataLocalTempbiber_tmp_8yB4library.bib_2388.utf8, line 6, warning: 172 characters of junk seen at toplevel

[2146] Utils.pm:320> ERROR - BibTeX subsystem: C:UsersAhmedAppDataLocalTempbiber_tmp_8yB4library.bib_2388.utf8, line 1269, syntax error: found "2013", expected ","

[2147] Biber.pm:128> INFO - WARNINGS: 2

[2147] Biber.pm:132> INFO - ERRORS: 1