My problem is the \AtBeginSection[] in the table of content

Question

Please I have a problem like this , At \AtBeginSection[] is not working. I used all your proposed solution but nothing.My template is like yours see above. So, when i applied such code : the result is produced like that. Please help me i need it as soon as possible. Thanks

\documentclass{bredelebeamer} 
\usepackage[frenchb]{babel} 
\usepackage[T1]{fontenc} 
\usepackage{inputenc} 
\usepackage{graphicx} 
\usepackage{url} 
\usepackage{xcolor} 
\usepackage{multimedia} 
\usetikzlibrary{arrows,shapes} 
\definecolor{myblue}{RGB}{33,84,157} 
\setbeamercolor*{structure}{bg=myblue!20,fg=myblue} 
\setbeamercolor*{palette primary}{use=structure,fg=white,bg=structure.fg} 
\setbeamercolor*{palette secondary}{use=structure,fg=white,bg=structure.fg!75} 
\setbeamercolor*{palette tertiary}{use=structure,fg=white,bg=black} 
\setbeamercolor*{palette quaternary}{fg=white,bg=black} 
\setbeamercolor{section in toc}{fg=black,bg=white} 
\setbeamercolor{alerted text}{use=structure,fg=structure.fg!50!black!80!black} 
\setbeamercolor{titlelike}{parent=palette primary,fg=structure.fg!50!black} 
\setbeamercolor{frametitle}{bg=myblue!85,fg=white} 
\setbeamercolor*{titlelike}{parent=palette primary} 
 \setbeamercovered{transparent}
 %l'autre option : invisible, cache totalement le texte pas encore découvert 
% (ie, n'utilise pas le ``grisé''). \setbeamercovered{invisible}

\begin{document}

\AtBeginSection[]{%
  \begin{frame}\frametitle{Table of Contents} 
     \tableofcontents[currentsection] 
  \end{frame}
}

\section{Introduction} \subsection{Context} \begin{frame} \frametitle{The immune system}

\end{frame}

\subsection{The dendritic cell algorithm} \begin{frame} \frametitle{The immune system}

\end{frame}

\subsection{Problem statement} \begin{frame} \frametitle{The immune system}

\end{frame}

\section{A revised DCA based on K-Nearest Neighbors (KNN)}

\subsection{Danger signal calculation process based on the 1-Nearest Neighbor} \begin{frame} \frametitle{The immune system}

\end{frame}

\subsection{Danger signal calculation process based on the K-Nearest Neighbors} \begin{frame} \frametitle{The immune system}

\end{frame}

\subsection{Example KNN-DCA} \begin{frame} \frametitle{The immune system}

\end{frame}

\section{Experimental Results} \begin{frame} \frametitle{The immune system}

\end{frame}

\section{Conclusion}

\begin{frame} \frametitle{The immune system}

\end{frame}

\end{document}