Sky Go customers are complaining of being unable to use the app to stream channels during three big sporting events.
It has been out of action as the Black Caps play Pakistan, during the rugby Sevens in Wellington and Ultimate Fighting Championship (UFC) screenings.
The app allows customers to screen Sky channels when away from their televisions.
Sky has said on its Facebook page: "Our tech teams are still working to resolve the issue with SKY Go login. I'll update you as soon as I have any developments. Sorry for the interruption to your Sunday online viewing."
Customers vented their frustration on the page.
Andy Roo said: "The one day where Sky Go is needed due to rugby and cricket on at same time but goes down. Does SKY GO only work with a maximum of 10 customers at 1 time as this reminds me of all the AB games and all cricket world cup."
Kim Morgan asked: "What is SKY GO doing to compensate those that have missed out on watching the Cricket or Rugby due to the so called technical difficulties?"