From that link on Digital Banking:

We will be carrying out routine maintenance from approx. 01:00 until approx. 08:00 this Sunday 24 September, and then from approx. 12 midnight until approx. 06:00 on Monday 25 September. Our Digital, Mobile, and Telephone banking services will be unavailable during these times. We are sorry for any inconvenience that this will cause and thank you for your patience.