Late last month, the first ever Pokémon Go festival was held in Chicago. Developer Niantic was no doubt hoping the game's one-year anniversary celebrations would help rekindle media interest in the AR title. And it did - but for all the wrong reasons.

Not only were the 20,000 attendees met by incredibly long queues to get in and out of the event, but most people couldn't even play the game because of server problems and overloaded cell towers.

Niantic attempted to placate the angry crowds, some of whom paid hundreds of dollars for tickets from resellers, by offering $20 face value refunds, the first legendary Pokémon, $100 of in-game Pokécoins, and more.

But it seems the company's efforts weren't enough. Niantic is now facing a class-action lawsuit brought against it by a California man who traveled to Chicago for the festival. It seeks unspecific damages against the developer and alleges that the event didn't live up to what was promised. The suit also seeks to represent other angry attendees.

"Fest attendees, many of whom like Plaintiff traveled to Chicago from other states or countries, had the reasonable expectation of arriving at Grant Park for a day of capturing rare 3D monsters with their friends, families, and other so-called Pokemon Go 'Trainers,' but the reality of the Fest fell flat in comparison to Defendant's promises," the lawsuit said. "Upon reaching Grant Park, Fest attendees encountered a 'three-mile line' and an unplayable Game."

In response to what happened in Chicago, Niantic has decided to postpone several Pokémon Go events set to take place in Europe this month. Anyone who planned to attend the August 5 meetups in Copenhagen and Prague, as well as the August 12 events in Stockholm and Amsterdam, will now have to wait until "later this fall."

Niantic says the reason for the delay is "to guarantee the best possible gameplay experience for European Trainers."