Why does \subsubsubsection not work?

Question

Why am I not use \subsubsubsection{My subsubsubsection}? I tried to use \paragraph but same result.

\documentclass[a4paper,12pt]{article} 
\usepackage[utf8]{inputenc}
\usepackage[T1]{fontenc}
\usepackage[french]{babel}
\usepackage{amsmath}
\usepackage{amsfonts}
\usepackage{amssymb} 
\usepackage{graphicx}
\usepackage[hmargin=2cm,vmargin=3cm,headheight=65pt]{geometry}
\usepackage{wrapfig}
\usepackage{enumitem}
\usepackage{float}
\usepackage{eurosym}
\usepackage{tabto}
\usepackage{listings}
\usepackage{xcolor}
\usepackage{titlesec}
\usepackage{xspace} 
\usepackage{fancyhdr}

\usepackage{lastpage} 
% References
\usepackage{biblatex}
%\addbibresource{references.bib}

\usepackage{hyperref} % put here <<<<<<<<<<<<<<<<<
\hypersetup{pdfstartview = {XYZ null null 1.00}} 
\usepackage{csquotes}
\colorlet{punct}{red!60!black}
\definecolor{background}{HTML}{EEEEEE}
\definecolor{delim}{RGB}{20,105,176}
\colorlet{numb}{magenta!60!black}
%HEADER <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<,
\renewcommand{\footrulewidth}{1pt}
\renewcommand{\headrulewidth}{1pt}
\fancyhead[C]{\leftmark }
\fancyhead[L]{\includegraphics[scale=0.15]{example-image-c}}
\fancyhead[R]{\includegraphics[scale=0.2]{example-image-c}}
%\fancyfoot[C]{\thepage}
\fancyfoot[L]{blabla}
\fancyfoot[R]{\textbf{\thepage /\pageref{LastPage}}}  % added  <<<<<<<<<<<<<<<
\fancyfoot[C]{\fbox{Confidential}} % added  <<<<<<<<<<<<<<<
\pagestyle{fancy}
\newcommand{\HRule}{\rule{\linewidth}{0.5mm}}
\newcommand{\hsp}{\hspace{20pt}}
\begin{document}
\begin{titlepage}
    \begin{sffamily}
        \begin{center}

            \begin{figure}[th]
                \includegraphics[width=5cm]{example-image-a}\hfill
                \includegraphics[width=5cm]{example-image-b}
            \end{figure}    
            \vspace{3cm}
            %  \textsc{\Large }\\[1.5cm]                    
            % Title
            \HRule \\[0.4cm]
            { \huge \bfseries blabla\\[0.4cm] }
            \HRule \\[1cm]
            %\includegraphics[width=12cm]{images/f5.png}                

            % Author and supervisor
            \Large  blabla\\
            \Large{blabla} \\
            \Large blabla\\[1cm]                

            \vspace{3cm}

            \begin{minipage}{0.4\textwidth}
                \begin{flushleft} \large
                    \emph{\textbf{blabla}}\\ 
                    \textsc{blabla}\\
                    \textsc{blabla}\\
                \end{flushleft}
            \end{minipage}
            ~
            \begin{minipage}{0.4\textwidth}
                \begin{flushright} \large
                    \emph{\textbf{blabla}}\\
                    \textsc{blabla}\\
                    \textsc{blabla}\\
                \end{flushright}
            \end{minipage}
            \vfill

            % Bottom of the page
            \vspace{1cm}
            {\large 2021 - 2022}

        \end{center}
    \end{sffamily}
\end{titlepage}
\newpage
\tableofcontents

\section{section}
some content
\subsection{subsection}
 some content
\subsubsection{subsubsection}
  some content
\subsubsubsection{subsubsubsection}
  some content

\vspace{-0.5cm}
\newpage


\end{document}