This usually means your game ROM is encrypted and the emulator cannot find a valid aes_keys.txt file. You must either supply the decryption keys or use a tool on your modified 3DS to decrypt the game into a .3ds format before transferring it to Android. Missing Text or Glitched Fonts
If you want to run a 3DS emulator on Android legally, here are lawful alternatives: 3ds Emulator Bios File Download For Android
Accessing in-game keyboard overlays or camera functionalities. The Legalities and Risks of Downloading BIOS Files This usually means your game ROM is encrypted