Failed to import LaTeX file into Mathematica

On Ubuntu 20.04.3 LTS, I try to import the following LaTeX file into Mathematica:

$ realpath MS.tex 
/home/werner/Downloads/2108.06678/MS.tex

In Mathematica, I use the following command:

A = Import["/home/werner/Downloads/2108.06678/MS.tex", "Notebook"]
NotebookPut[A]

But the following error is triggered:

Any hints for fixing this problem will be highly appreciated.

Regards,
HZ

You may try

NotebookPut@Import["/home/werner/Downloads/2108.06678/MS.tex", "TeX"]

Still failed, as shown below:

Does it fail for that particular TeX file only? Have you tried with a minimal TeX file?

Indeed, I retested using the following example file:

$ realpath example.tex 
/home/werner/test/example.tex

$ cat example.tex 
\documentclass{article}
\begin{document}

The well known Pythagorean theorem \(x^2 + y^2 = z^2\) was 
proved to be invalid for other exponents. 
Meaning the next equation has no integer solutions:

\[ x^n + y^n = z^n \]

\end{document}

The results show that all the methods discussed here are vaild:

NotebookPut@Import["/home/werner/test/example.tex", "TeX"]

or

NotebookPut@Import["/home/werner/test/example.tex", "LaTeX"]

or

A = Import["/home/werner/test/example.tex", "TeX"]
NotebookPut[A]

or

A = Import["/home/werner/test/example.tex", "LaTeX"]
NotebookPut[A]

See the following screenshot for more details:

There must be something offending in your file MS.tex. If it is really important to you, you may try to track down the problem by removing parts of the TeX file and see what happens.

I see. Thank you for your advice and help.