Problem with Figure

Question

If I do the following:

\begin{figure} 
    \includegraphics[width=0.5\textwidth]{steiner-output.jpg}
    \caption{Visualisation of connected brain regions using Steiner minimal tree.}
    \label{fig:vis1}
\end{figure}

I get something like:

But if I change the code to:

\begin{figure*} 
    \includegraphics[width=0.5\textwidth]{steiner-output.jpg}
    \caption{Visualisation of connected brain regions using Steiner minimal tree.}
    \label{fig:vis1}
\end{figure*}

The graphics disappears from the pdf. Can anyone tell me why and what am i doing wrong?

I can provide a link to an working example if needed.

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Here is a link to a minimal example where you can see the problem. The latex file has the same graphics twice, once as figure and the second as figure*. You will see the first shows up but the second one doesn't.

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Here is an link of the files of overleaf. This should remove the security concerns. Ones its solved, I can upload the exact part the code causing the problem which may be more achievable.