Arch Linux

Hi, i have a very old asus laptop, some years ago i installed arch with xfce. I leaved this laptop untouched for some months, then 2 days ago I rebooted the sistem and did the classic sudo pacman -Syu after a lot of downloading i got an error about gpt keys, searching obline it was something like this:

`> error: celt: signature from "Jan Alexander Steffens (heftig) " is unknown trust

:: File /var/cache/pacman/pkg/celt-0.11.3-3-x86_64.pkg.tar.xz is corrupted (invalid or corrupted package (PGP signature)). Do you want to delete it? [Y/n] `

The only issue i noticed after is that even if im connected to internet (wifi or lan) from midori It wont be able to load anything. How can i fix this? Thnx in advance for the help guys!