Use matrices in TikZposter environment?

I am trying to create a poster using TikZposter. I would like to have some math involving matrices in my poster. When I do:

\documentclass{tikzposter}
\usepackage{amsmath}
\usetheme{Default}
\begin{document}
\block{My Block}{
Some text\\
\begin{align*}
M+A=T+H
\end{align*}
}
\end{document}


everything works fine, but as soon as I try to include a matrix:

\documentclass{tikzposter}
\usepackage{amsmath}
\usetheme{Default}
\begin{document}
\block{My Block}{
Some text\\
\begin{align*}
\begin{matrix}
M & A \\
T & H
\end{matrix}
\end{align*}
}
\end{document}


MikTex complains with over a hundred error messages and does not generate an output. Am I doing something wrong? How can I fix this? Will I have to avoid using matrices all together? Thanks for any suggestion!

Can't say why, but as an alternative you can use array. Note that you should never use \\ before a displayed math environment (such as align, equation and gather), and for single line equations you generally don't want to use align/align*, but equation/equation* (see align vs equation and Which command should I use for displayed equations?).

\documentclass[a2paper]{tikzposter}
\usepackage{amsmath}
\usetheme{Default}
\begin{document}
\block{My Block}{
Some text
\begin{equation*}
\begin{array}{cc}
M & A \\
T & H
\end{array}
\end{equation*}
With delimiters:
\begin{equation*}
\left(  \begin{array}{cc}
M & A \\
T & H
\end{array}
\right)
\end{equation*}
}
\end{document}