As the Diablo 4 beta approaches, we can't help but dread a demon from our past: Error 37

pcgamer.com:

Remember Error 37? We first encountered it on May 8, 2012, one week before the launch of Diablo 3, when Blizzard gave us a heads-up that the error might pop when we tried to get into the game on launch day—but it was "no cause for concern,(opens in new tab)" they told us. Just, you know, give it a minute and try again.

Of course, it very much was a cause for concern. The Diablo 3 launch was «shaky,» as we put it (very gently) in our summary(opens in new tab) of the release day situation. Servers were crushed as people struggled for hours to get in: Our "review as it happens(opens in new tab)" reflected the mood of the moment, calling the rash of errors, disconnects, and progress resets «utter bullshit.» 

Blizzard was able to get things stabilized for most players within a day or two, and we ultimately gave the game an outstanding 90% in our full review. But the scars remain on Metacritic(opens in new tab), where Diablo 4 to this day holds a lowly 4.2 rating across more than 10,000 user reviews. 

And the mess reverberated beyond just review scores and angry comments: Blizzard refused to issue refunds to frustrated players in South Korea, which led to formal complaints and a stern talking-to from that country's Fair Trade Commission. Attitudes were quickly adjusted, and a few weeks later Blizzard's «no refunds» policy fell by the wayside(opens in new tab). (In South Korea, at least.)

And despite all the years past, fans haven't forgotten:

What was particularly infuriating about the whole Error 37 debacle is that it prevented players from accessing Diablo 3 at all, even if they wanted to play the singleplayer campaign. Diablo 3 is always online, even if you're playing by yourself: Blizzard co-founder Mike Morhaime explained