\usepackage{eurosym}
\usepackage{ragged2e}
\usepackage{multicol}
\usepackage{hyperref}
\usepackage[utf8]{inputenc}
\usepackage{ngerman}
\setbeamertemplate{navigation symbols}{}
\setbeamercovered{invisible}
\usetheme{Ilmenau}
\definecolor{ffred}{RGB}{220,0,103} % changed this
\definecolor{ffyellow}{RGB}{255,180,0} % changed this
\definecolor{ffblue}{RGB}{0,158,224} % changed this

\setbeamercolor{normal text}{fg=black,bg=white}
\setbeamercolor{alerted text}{fg=ffblue}
\setbeamercolor{example text}{fg=ffblue}

\setbeamercolor{structure}{fg=ffred}

\setbeamercolor{background canvas}{parent=normal text}
\setbeamercolor{background}{parent=background canvas}

\setbeamercolor{palette primary}{fg=black,bg=ffyellow} % changed this
\setbeamercolor{palette secondary}{bg=ffyellow,fg=black} % changed this
\setbeamercolor{palette tertiary}{bg=ffred,fg=black} % changed this
\setbeamertemplate{frametitle}
{%
\vspace{-0.165ex}

\begin{beamercolorbox}[wd=\paperwidth,dp=1ex, ht=4.5ex, sep=0.5ex, colsep*=0pt]{frametitle}%
    \usebeamerfont{frametitle}   \strut \insertframetitle  \hfill \raisebox{-1.6ex}[0pt][-\ht\strutbox ]{ \includegraphics[scale=0.2]{logo-transparent.png}}
    \end{beamercolorbox}%
 }%

 \AtBeginSection{
	   \let\insertsectionnumber\relax
	     \let\sectionname\relax
	       \frame{\sectionpage}
       }
 \AtBeginSubsection{
	       \let\insertsubsectionnumber\relax
	         \let\subsectionname\relax
		\frame{\subsectionpage}}