I cannot enter my account on Facebook: I get this message:

The computer and internet account where I try to access the account is the same oen I used since I created the account in 2013. I do not remember having linked any mobile phone to this account, I also do not have a smart phone able to connect to the internet. I already changed my password through the Google account twice but I always get to this message.

It looks like you haven’t logged in from this browser before. Please enter the security code from your phone below.

Could you please explain me what is happening? What do I need to do to keep using this account?