HBO’s “House of the Dragon” premiered with massive numbers on Sunday night, with 9.99 million viewers tuning in across HBO and HBO Max. This makes the “Game of Thrones” spinoff HBO’s most-watched series premiere in the network’s history.

This success didn’t come without a slight glitch: more than 3,700 were reported across HBO Max on Sunday night, taking place just before the show started airing at 9 pm.ET. “‘House of the Dragon’ is being successfully viewed by millions of HBO Max subscribers this evening. We’re aware of a small portion of users attempting to connect via Fire TV devices that are having issues and are in the process of resolving for those impacted users,” the HBO statement said.

That said, the premiere numbers are massive. The company said that the Sunday night numbers typically represents around 20% to 40% of the show’s total audience. “It was wonderful to see millions of ‘Game of Thrones’ fans return with us to Westeros last night,” said Casey Bloys, chief content officer for HBO and HBO Max.

“House of the Dragon” tells the story of the Targaryen civil war, which took place around 200 years before the events in “Game of Thrones.” It is based on Fire & Blood novel by George R.R. Martin which tells the story of the House of Targaryen. The 10-episode series will be released weekly.