Diablo II: Resurrected fans are not happy. Not more than an hour after launch, players are seeing multiple error messages like "Failed to Enter Game. Character Could Not be Found." Players are locked out of current characters, and when trying to create a new character, the game will send an "Unable to Connect " message.
As fans were quick to flood social media and the in-game lobby chat with complaints, Blizzard has responded to the problem. Both their Twitter and Battle.net launcher has a message to fans, "We're currently looking into issues that prevent some players from seeing existing characters or creating new characters."
Failed to Enter Game, Character Could Not be Found: How to Fix Error in Diablo II: Resurrected
As of now, there is nothing you can do, but wait. Just based on the massive Twitch numbers, it seems Blizzard was unprepared for the number of players. This is a bit of a let down considering the hype around this launch and the poor launch of Warcraft III: Reforged. Blizzard was apologetic for years after the massive failure of Reforged and promised a much different product for Resurrected. So far, the reviews have been positive, but there is nothing worse than simply not being able to play.
Hopefully, Blizzard will find a fix soon.