This endpoint verifies the provided credentials (such as email, username, and account ID) and, upon successful authentication, generates bearer tokens for impersonation. These tokens enable the master account to perform administrative actions on behalf of sub-accounts without requiring direct login credentials for each one. The response includes both a standard API token and a SaaS access URL for seamless navigation and integration. This endpoint is essential for organizations or agencies that centrally manage several business units, providing secure, auditable, and efficient access control across all associated accounts. If the credentials are invalid or the master account does not have permission to access the requested sub-account, an appropriate error message is returned.