[Tails-dev] sig key broken?

C:\Users\1\Downloads\Tails>gpg --verify tails-amd64-4.1.img.sig
gpg: assuming signed data in 'tails-amd64-4.1.img'
gpg: Signature made 12/03/19 01:12:54 GTB Standard Time
gpg:                using RSA key FE029CB4AAD4788E1D7828E8A8B0F4E45B1B50E2
gpg: Can't check signature: No public key

from what i know it should not say "gpg: Can't check signature: No public key" is a problem with the iso image ?