In order for the authorization to work in non-interactive mode you will need to generate a token on your administrator page, then download and store it where you prefer on the local file system. When you will launch the client you will have to specify where the token is stored so that the client can authenticate in behalf of you, using the
--auth-file=/path-to-file argument: as soon as the token is not revoked or deleted the client will be able to function without any interaction with the user and all the operation will be linked to your account.
Another option is to simply set the environment variable METERIAN_API_TOKEN to the value of the token. In a Linux shell for example:
$> export METERIAN_API_TOKEN=12345678-90ab-cdef-1234-567890abcdef
When this variable is known Meterian will recognize the token and it will be able to proceed with the scan.