Unable to login to Neko account on new phone

Hi all! I've been using Neko for over 1.5 years now. A few days back I bought a new phone and I'm trying to login to my Neko account but it keeps giving me an error saying "Something went wrong". The account is still logged in on my old phone because I was worried I may not be able to log back in and it will give me the same error on my old phone if I tried to log back in there

Is it because a) I'm not using the latest version of the app b) I need to first logout from my old phone first

If not the above reasons does anyone know a solution for this? Thanks in advance!