Google Domains is a service that can be turned off for your G Suite organisation. A G Suite administrator can turn the service on or off for individuals, for organisational units or for the entire organisation.
If you are not a G Suite administrator, follow the instructions in Google Domains has been disabled for your organisation.
If you are an administrator of your organisation's Google Accounts, you can control who uses Google Domains. Just turn Domains on or off for those users in your Admin console. Users who have Domains turned on can purchase new domains (such as example.com), and manage domains from their account.
Before you begin: To turn the service on or off for selected groups of users, put their accounts in an organisational unit.
To turn Google Domains on or off for an organisation or select group of users: