Android phones, apps and tablets

For a ridiculous set of reasons I'm trying to set up an ancient gt-s5830i just for whatsapp after stupidly doing a factory reset.

Long shot but I don't suppose anyone could help?

Issue: When I try and login to my google account it won't log in.

• it is connected to wifi
  
• my google account isn't an @gmail
  
  

it says;

you need to link a Gmail account with this phone.
you already have a gmail username (my not@gmail.com) associated wiht this account, but it is not currently active.
Touch next to re-activate this username and use it with your phone
or if you want to use a different account, press the back button and sign in with a different account.

Once I click next it says;

a problem occurred while communicating with google servers.

The original phone was / is locked on 02.

My thinking is that it's just too old and the OG bloatwear is stopping it. My thought is whether I can somehow properly wipe it and reinstall new software on it to allow me to log in.

Any ideas welcome.