Try to go nearer to your router.
I had this problem when my connection was bad.
It disconnected very often and when it connected again,it asked me for my password again,even if I saved it.
And the internet was very slow,nearly unusable.
Bringing a lower distance between my laptop and my router solved it.

Olá, brunorafa!
Tente chegar mais perto do seu wifi, como nipos disse, e também tente reiniciar o gerenciador de rede:



Espero que consiga,
romao

How is the issue now?