適切に: "gpg: 主キーがありません。"しかし、鍵は期限切れではありません。

期限切れのない良いGPGキーがありますが、実行すると

aptly -architectures=all publish repo product
Warning: publishing from empty source, architectures list should be complete, it can't be changed after publishing (use -architectures flag)
Loading packages...
Generating metadata files and linking package files...
Finalizing metadata files...
Signing file 'Release' with gpg, please enter your passphrase when prompted:
gpg: no default secret key: secret key not available
gpg: signing failed: secret key not available
ERROR: unable to publish: unable to detached sign file: exit status 2

なぜ？