Game-maker Niantic has postponed today’s scheduled launch of Pokémon Go in Japan following an email leak.

Yesterday we reported that the game was due to go live in Japan today (Wednesday), but the companies behind Pokémon Go have canceled that plan, a source close to the launch told TechCrunch. One major reason for that change of heart is that internal communication from McDonalds Japan, the game’s sponsor, detailing the launch made its way to internet forums (including 2ch, “Japan’s Reddit”) and photo site Imgur.

An initial morning launch time was pushed back to early afternoon as the email went viral. Later, however, the companies decided to cancel today’s launch entirely due to concerns that the hype generated would overload the game, our source explained. We don’t have an immediate update on when the game will finally go live in Japan, but understand that the launch is “imminent” but unspecified.

The postponement will frustrate many in Japan who are still waiting but, on the positive side, Niantic, Nintendo and the Pokémon Company — the three firms behind the smash game — are confident that, if the game is launched right, their serves can handle the undoubtedly huge demand that Pokémon Go will generate in Japan. Ninatic CEO John Hanke previously cautioned that the company needed time to ensure it had enough servers to cope with a deluge of Pokémon addicts in Japan.

The delay means also that we will have to wait to see the impact of the first “sponsored location” in the game. McDonalds has agreed to become the first paying sponsor, turning its 3,000 stores in Japan into “gyms” where players can battle, adding a new source of revenue to the game beyond its already lucrative in-app purchases and potentially driving real-world traffic to McDonalds stores. That’ll be a partnership to watch since there are plans to offer sponsored locations in other parts of the world.

The success of Pokémon Go is unprecedented. Just two weeks after its U.S. debut, it has reportedly passed 30 million downloads and $35 million in revenue, and surpassed Twitter on active users and Facebook on engagement. That has doubled the valuation of Nintendo — yes, in just two weeks — and all without launching in Japan, the home of Pokémon, yet.

Pokémon Go is available in more than 30 countries right now thanks to a steady rollout across Europe last week. TechCrunch understands that Japan is planned as the first launch in Asia and, once the game is available there, it will be extended to other countries in the region.

Article updated 20/07 22:10 PDT to further clarify the change of plan and our sourcing of information