Niantic apologised for technical issues that created problems for players attending a sold-out event called Pokemon Go Fest in Chicago on 22 July, although July 23 marked the day players pent a whopping $5.8 billion in the game.

CEO John Hanke (pictured) said the issues were due to “oversaturation of the mobile data networks of some network providers”, and added that “We will be incorporating all of our learnings” into the Pokemon Go events planned for later this summer in Yokohama, Japan and across Europe.

To make up for the disappointment, participants will not only get their ticket refunded and receive $100 in PokeCoins, they will also get a ‘legendary Pokemon’ called Lugia.

Originally Niantic had said that the first legendary Pokemon (described as rare and powerful) would be unveiled at the event, if users globally were able to catch enough Pokemon during the ‘Pokemon Go Fest Challenge Windows’.

What’s more, special Pokemon, eggs, and check-in PokeStops appearing during the event had their range increased to a two mile radius surrounding the venue and were only visible to attendees.

Despite the event not going as planned, Sensor Tower announced that Pokemon Go “clocked its biggest single day of player spending outsid of its launch window” with players spending $5.8 billion on 23 July, the day two legendary Pokemon were launched.

This was just over a year after launching in its first territories, and more than eight months since a limited-time Halloween event, where the game earned $23.3 million worldwide between 25 and 29 October.

Currently, the game ranks number one for iPhone revenue in 23 countries, including the US, Canada, France, Germany, and Great Britain, the report said.

About 60 million people still play Pokemon Go each month, according to app research firm Apptopia, and one in five of these open the game on a daily basis.

Over the past year the app has been downloaded 755 million times and earned more than $1.2 billion in revenue.

According to Bloomberg, Niantic CEO John Hanke was booed when he took to the stage. The report added the company is working on new advertising deals in partnership with retailers to sponsor locations.

This is not the first time Niantic has had technical difficulties. In its first month, Pokemon Go had server issues which made the game almost unplayable.