"Talk about great service, your website now didn't accept credit card payments, and now just crashes, tried to book the fight online, didn't work, no one answering your phones, what a bunch of muppets," one Facebook user wrote.
Sky spokeswoman Kirsty Way said there had been issues with the website but people were never going to be able to book to view the fight on the website tonight.
"We advertised the 0800 number and Fanpass... We did have Sky site issues unfortunately but even if we didn't, you could not book that way."
It wasn't the first time there was glitches with Sky during a major sporting event.
Sky Go, which allows streaming on devices such as laptops, tablet computer or mobile phones, was out of action January 31, leaving customers unable to watch the Black Caps playing Pakistan, UFC and the rugby sevens in Wellington.
Its live streaming service was also down in May for more than three quarters of the NBA match between Steven Adams' Oklahoma Thunder and the Golden State Warriors.
It was fixed just in time for the final five minutes. However, Twitter users were unimpressed, with one person calling the situation a "disgrace".
Sky chief executive John Fellet later admitted the service wasn't good enough but said Sky wasn't looking to abandon the service.