Availability of Network Partner’s Service. The Network Partner shall provide its Invoice Issuers with its eBill Solution within the limits of availability of its existing network. The Network Partner shall reasonably ensure that no un- scheduled interruptions occur. Maintenance works shall be generally performed outside of business hours within maintenance windows with a prior notice provided by the Network Partner to SIX in a suitable manner. The Network Partner shall ensure it is authorized to suspend or block operation of or access to the service for its Invoice Issuers at any time for important reasons (such as faults, sabotage, risk of misuse, etc.). The Network Partner shall notify SIX of measures taken accordingly in a suitable manner.