Vagrant box won't provision

[seven1m]

    default: Downloading https://github.com/rvm/rvm/archive/1.29.7.tar.gz
    default: Downloading https://github.com/rvm/rvm/releases/download/1.29.7/1.29.7.tar.gz.asc
    default: gpg:
    default: Signature made Thu 03 Jan 2019 10:01:48 PM UTC using RSA key ID 39499BDB
    default: gpg:
    default: Can't check signature: public key not found
    default: GPG signature verification failed for '/home/vagrant/.rvm/archives/rvm-1.29.7.tgz' - 'https://github.com/rvm/rvm/releases/download/1.29.7/1.29.7.tar.gz.asc'! Try to install GPG v2 and then fetch the public key:
    default:     gpg --keyserver hkp://pool.sks-keyservers.net --recv-keys 409B6B1796C275462A1703113804BB82D39DC0E3 7D2BAF1CF37B13E2069D6956105BD0E739499BDB
    default: or if it fails:
    default:     command curl -sSL https://rvm.io/mpapis.asc | gpg --import -
    default:     command curl -sSL https://rvm.io/pkuczynski.asc | gpg --import -
    default: In case of further problems with validation please refer to https://rvm.io/rvm/security
The SSH command responded with a non-zero exit status. Vagrant
assumes that this means the command failed. The output for this command
should be in the log above. Please read the output to determine what
went wrong.