Nintendo’s hotly awaited mobile title “Mario Kart Tour” launched on Wednesday, with many users initially complaining that server overload meant they were unable to play the game — seen as a major test of the Kyoto-based company’s mobile ambitions.

Expectations have been high for the title, where users steer characters such as Bowser, Yoshi and even Mario’s first love interest, Pauline, as they race karts through world cities, with New York the launch location.

“The servers are experiencing heavy traffic. Your log-in request will be processed in the order it was received,” read a message that appeared when the game was launched.

A Nintendo spokesman said the company was aware that due to heavy traffic, some users were having trouble accessing the game, but that the situation was improving.

Nintendo has been slow to expand into mobile gaming, choosing to focus on its hybrid Switch console. Its online subscription gaming business has lagged behind rivals Sony and Microsoft.

“Mario Kart Tour,” which risks disappointing gamers with its initial lack of a multiplayer option, includes an in-game currency that can be used to try to win rare characters and items and a $4.99 monthly subscription to unlock in-app rewards.

The game’s teething problems came after Nintendo launched a lower-priced, handheld-only version of its $300 Switch console last Friday, aiming to provide an alternative to its aging 3DS device and encourage people to buy multiple Switch units.

In Japan, the Switch Lite is estimated to have sold around 180,000 units in its first three days on sale, based on data in industry magazine Famitsu.

Nintendo’s shares sold off on the data, closing down 4.3 percent ahead of the “Mario Kart Tour” game launch. The gaming company’s shares have climbed almost 40 percent this year.