Downloading required keys

downloading required keys...
error: key "5F702428F70E0903" could not be looked up remotely
error: required key missing from keyring
error: failed to commit transaction (unexpected error)
Errors occurred, no packages were upgraded.

sudo pacm-key --refresh-keys", and received this output:

gpg: refreshing 80 keys from hkp://pool.sks-keyservers.net
gpg: connecting dirmngr at '/root/.gnupg/S.dirmngr' failed: IPC connect call failed
gpg: keyserver refresh failed: No dirmngr
==> ERROR: A specified local key could not be updated from a keyserver.

Поможет

dirmngr < /dev/null
pacman-key --refresh-keys
pacman -Syyu