Updated at 9:08 p.m. Pacific.

Curses are normally a bad thing, but so many people are lining up to catch Blizzard’s Curse of Naxxramas that it is potentially causing some issues for the developer’s collectible-card game.

Hearthstone: Heroes of Warcraft got its first add-on less than an hour ago. Players are rushing to purchase the single-player adventure, but many people are running into connection problems, bugs, and other issues. Later in the day, latency and server-stability issues also hit, making for a slow, inconsistent experience.

When the game first launched around 11 a.m. Pacific time, the in-game store was closed for many people seeking to spend some cash on the add-on. This problem seems intermittent, and now most people are online playing Naxxramas — and that’s when others are discovering separate issues. A number of players are reporting that the game crashes after a fight with the character Maexxna. Some are even saying that they defeated the spider lord, but Hearthstone registered it as a defeat.

We’ve reached out to Blizzard about these problems, and we’ll update this post with any new information.

Prior to the release of Naxxramas, Blizzard posted a message to the game’s website saying it is aware of some people running into problems making purchases. The influx of fans all trying to buy the downloadable content and play it at once is likely causing the problems with the store. As for the Maexxna fight, that is likely a bug that the developers will quickly patch.

Curse of Naxxramas is a five-part adventure (as Blizzard calls it) for Hearthstone. The first part launched today, and the rest will debut over the next few weeks. While the card battler is free-to-play, the company is selling access to this expansion for $7 per episode or for $25 for the whole thing. For a limited time, however, the first episode is free and gamers can purchase the rest of the episodes for $20.