Air Mahjong is a real-time 3D board, so it needs two things this browser has not given it: WebGL 2, and an engine new enough to run the game code. A browser with hardware acceleration switched off is the usual reason, and so are older smart TVs.
Open it on a laptop, a desktop or a phone instead — nothing is installed and nothing needs signing up for.
If you are on a desktop browser, check that hardware acceleration is enabled in its settings; that is the fix in almost every case.
Air Mahjong is a real-time 3D board, and it needs WebGL 2. iPhone and iPad Safari have had that since iOS 15, and a current phone can run this board. This page asked for a context and Safari did not keep one.
On an iPhone the usual causes are Low Power Mode, too many open Safari tabs — iOS only keeps a few WebGL contexts at once — or an iOS older than 15. There is no hardware-acceleration switch to flip, unlike on a desktop.
Turn Low Power Mode off, close the other tabs, and reload. If this phone is on iOS 15 or newer and the board still does not open, the GPU refused the context. The same link on a laptop or desktop will.
The board itself never started. The game code either did not arrive or stopped while starting, which is a different failure from a missing graphics chip.
Reload the page. On an iPhone, turn off content blockers for this site and open it in Safari rather than inside another app. Nothing is installed and nothing needs signing up for.