An arrangement (106), such as a server apparatus or a plurality of at least functionally connected server and/or other apparatuses, for controlling access to a network service, such as a cloud service, utilizing multi-factor, at least two- factor, authentication, comprising a processing entity (150) and a memory entity (152) for processing and storing data, respectively, and a data transfer entity (156) for receiving and sending data, the arrangement being configured to transmit a code (143c), preferably as browser data such as web page data, during a communication session associated with a predetermined user of the service for visualization and subsequent uttering by the user, receive sound data (143g) indicative of the uttered code, determine on the basis of the sound data and voiceprint data associated with the predetermined user whether the code has been uttered by the predetermined user (143h), and provided that this seems to be the case, raise the gained authentication status of the predetermined user regarding at least the current communication session (143l), wherein raising the authentication status optionally includes at least one action selected from the group consisting of: enabling a new service feature, enabling the use of a new application, enabling a new communication method, and enabling the adjustment of service settings or preferences. A corresponding method is presented.