  $\mathrm{AuSn_4}$ is the example of an orthorhombic compound that exhibits
topological properties. Recent XRD measurements reveal an ambiguous nature of
the crystal structure, as it can be realized with either Aea2 or Ccca symmetry.
Motivated by this, we analyze the dynamical stability of the compound with
these symmetries. Interestingly, our main result indicates that
$\mathrm{AuSn_4}$ is unstable with both Aea2 and Ccca symmetries, due to the
soft modes in the phonon spectra. We find that the $\mathrm{AuSn_4}$ can be
stable with Pbcm at low temperatures using the soft mode analysis. We also show
that the theoretical electronic spectra are well reproduced, and have a good
resemblance with the experimental ARPES spectra. Our findings may be valuable
to the theoretical investigations of $\mathrm{AuSn_4}$ in future.
