Hi @CIX,
Is rinkeby network setup ok (feel free to share your setup)?
You could try npx oz accounts to check the setup.
Please note: We’ve decided it’s best to focus our upgradeability efforts on the Upgrades Plugins exclusively, and have halted development on the OpenZeppelin CLI. We will continue to provide support for the CLI until the end of 2020.
See: Building for interoperability: why we’re focusing on Upgrades Plugins