  We show that from an appropriate manipulation of the biconfluent Heun
differential equation can obtain the correct expression for the energy
eigenvalues for the Klein-Gordon equation without potential in the background
of Som-Raychaudhuri space-time with a cosmic string as a case particular
($k_{L}=0$) of [Vit\'{o}ria et al. Eur. Phys. J. C (2018) 78:44], in opposition
what was stated in a recent paper published in this journal [F. Ahmed, Eur.
Phys. J. C (2019) 79:682].
