Fantasy football turned into something of a nightmare for some players on Sunday, as ESPN's premier application faltered on the first day of the National Football League season, leaving millions of users in the dark.

Numerous users —including a sitting U.S. senator—took to Twitter to complain that the application wasn't working.

Claire McC tweet

Almost five hours after first acknowledging the outage, ESPN Fantasy Sports tweeted that it had fixed the issue — but many irate fantasy users were far from placated.

Fantasy tweet