maybe a

> pacman -S ca-certificates

will help. I remember (faintly) that the ca-certificates package said something like "valid until 20.10" or something like that "next check 20.10" - not sure.

Or you do a

> pacman -Syu

Which is the Arch Linux way of "apt-get update & apt-get upgrade"

edit:

Or you have a simple networking problem. Try a

> ping 8.8.8.8

if that works. If yes, update as said above. If no, you have to get your VM networking right  first. But that is a matter of the VM configuration, not of the OS running inside the VM.