You need to remove (or add # to the start of) the lines referring to “Community” in /etc/pacman.conf so it looks more like this:
[core]
Include = /etc/pacman.d/mirrorlist
[extra]
Include = /etc/pacman.d/mirrorlist
# If you want to run 32 bit applications on your x86_64 system,
# enable the multilib repositories as required here.
[multilib]
Include = /etc/pacman.d/mirrorlist
Notice mine is missing those “Community” lines entirely, since I (carefully!) merged the pacnew which appeared at the time the repo was deprecated.
The Community repository have finally been removed. Yow will likely need to attend to a number of .pacnew files; you could do worse than to check
pacdiff -o
… and have a look here: