On Disney+’s first day, its initial 10 million subscribers were hit with a series of outages. The company says this was because of high demand and the way engineers “architected the app.”

Ahead of the launch, Disney executives thought they would be ok. Michael Paull, head of Disney Streaming Services, told The Verge in August that years of handling big streams (like Game of Thrones premieres and finales) prepared the team for a launch of this size. It didn’t.

New subscribers couldn’t log in to the app; if they managed to get in, streaming was nearly impossible. People thought it might be issues with Amazon or third-party platforms carrying the app, but Kevin Mayer, head of Disney’s direct to consumer division, denied those rumors.

“It had to do with the way we architected the app,” Mayer said. “It was not Amazon.”

Disney+ runs on BAMTech technology — the same streaming service that saved Game of Thrones fans from dealing with HBO Go streaming problems when HBO Now launched. BAMTech also used to host MLB’s digital services, and proved throughout the years to be reliable. Mayer argued that although BAMTech has dealt with high volume streams in the past, that group had never seen the traffic that Disney+’s launch day brought in.

“We’ve never had demand like we saw that day and what we’re continuing to see,” Mayer said. “There were some limits to the architecture that we had in place were made apparent to us that weren’t before.”

Subsequent problems, including glitches within the app affecting where a movie picks off when people click “continue watching,” are also being fixed. “It’s a coding issue,” according to Mayer, “and we are gonna recode it.” Client updates to the app’s software are expected to roll out within the next couple of weeks, Mayer added.

Problems with big launches are expected. The gaming industry has dealt with surge issues when an influx of players try to get onto a server causing outages. This is a new ballgame for Disney. Something Mayer acknowledged after going through a product launch of his own is how much more respect he has for Netflix. Unlike Disney+, Netflix might not have 10 million people trying to sign up at once, but the streaming service has 160 million customers around the world who can access Netflix with very little outage problems.

“Netflix is operating their platform at a massive scale,” Mayer said. “I respect that. Having now gone through this launch, I see how difficult it is.”

Mayer added that he hopes, within a couple of years, that “we’ll be knocking on that door” and have a technology platform just as strong as other streaming competitors who have spent years figuring it out.