Because the running memory of your mobile phone is not enough to run the game you downloaded. Some games and software will take up a considerable amount of mobile phone memory when running, just like computer games take up memory chips, but when your memory is not large enough, you can't run naturally, even if the mobile phone system is high enough. Even if it is installed on a memory card, when you start running the game, you still need to occupy the cache of the mobile phone, that is, random storage, so you still need to have enough mobile phone running memory.

In some cases, you can uninstall other software on your phone to reduce the use of some caches. There is also the incompatibility between games and mobile phones. However, this situation is relatively rare.