It looks like your resume function is not properly set.
You need a swap partition entry in your /etc/fstab,
then
resume=UUID=place here the swap partition UUID
somewhere after the first " in the line starting
GRUB_CMDLINE_LINUX_DEFAULT="
of your /etc/default/grub
and the resume hook set at the end of
HOOKS=(base .... resume)
within the brackets in your /etc/mkinitcpio.conf.
At the end run
sudo mkinitcpio -P
sudo update-grub
and reboot.