Juju bootstrap for MaaS fails - Server Error ‘NoneType’ object for has no attribute ‘update’

Error:
Cannot start bootstrap instance: unexpected: Server Error: 400 BAD REQUEST (Failed to render preseed: ‘NoneType’ object has no attribute ‘update’)

Command:
juju bootstrap --bootstrap-series=focal --constraints tags=juju --config=config.yaml juju-cloud juju-controller --debug

Using

  • MaaS - 2.9.2 stable and
  • Juju - 2.8.9 - stable version

Full Error in image is available in the link below:
https://ibb.co/qRXQqZQ