Totally normal! This happens because our servers connect to your account from a new location/device. Very similar to when you first sign in to Linkedin from your phone or a new computer. You'll receive a pin code to your email, which you then just paste into our dashboard when it asks you.
Open your browser and login to linkedin.com
Right click anywhere on the linkedin.com website -> select 'Inspect' -> Application
Scroll down, to find the cookie named li_at and copy the value of that cookie. Please make sure you copy the whole value of the li_at cookie.