Nokia Account service was discontinued in April 2015, i.e. 3 years ago.
Regarding Whatsapp on your S40 device:
"For the following operating systems, you can no longer create new accounts, nor reverify existing accounts. However, you'll be able to continue using WhatsApp on:
- Nokia S40 until December 31, 2018
- Android versions 2.3.7 and older until February 1, 2020
Note: Because we'll no longer actively develop for these operating systems, some features might stop functioning at any time."
Source: https://faq.whatsapp.com/en/android/26000006/
No idea about your browser problem, which browser are you using ?