Here's why:
* The Nintendo Wi-Fi Connection service officially shut down in 2014. This means that all online features, including Mystery Gift distribution via Wi-Fi, are no longer available.
* Mystery Gifts were primarily distributed through this service. While some events offered limited-time Mystery Gift codes, the vast majority were delivered online.
However, there are still ways to get some Pokemon and items that were previously available through Mystery Gifts:
* Using a physical cartridge with the data still intact. If you have a cartridge of Diamond that has never been connected to the internet, it may still contain some Mystery Gift events that were automatically downloaded when the game was first released.
* Trading with other players. You can trade Pokemon with other players who may have already received Mystery Gift Pokemon or items.
* Using fan-made emulators and save files. This method is not officially endorsed and can potentially compromise your device, but some emulators allow access to save files that contain Mystery Gift content.
It's important to note that:
* Using emulators and save files can be illegal and against the terms of service of the game.
* You should always backup your save files before using any third-party tools.
While getting Mystery Gifts through Wi-Fi is no longer possible, you can still explore other ways to add to your Pokemon collection and experience the game to its fullest!