$ sudo pacman -S nextcloud-client
resolving dependencies...
looking for conflicting packages...

Packages (3) libcloudproviders-0.3.1-2  qtkeychain-0.11.1-1  nextcloud-client-2.6.4-1.parabola1

Total Installed Size:  10.99 MiB

:: Proceed with installation? [Y/n] y
(3/3) checking keys in keyring                                                                                                                 [#######################################################################################] 100%
downloading required keys...
error: key "3B94A80E50A477C7" 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.