Step one: Try again with heartgold. See if it works.
If yes, it’s an issue with your platinum.
If no, it’s an issue with your consoles or your Gen 5 game.
Step two (if no): Try another console.
If yes, it’s the console that’s the issue
If no, it’s probably the game.
Step three (if no):
Make sure the following:
- It’s in box one
- there’s no hms
Step four, if no:
-trade your Pokémon to HG, then try again.
If it works, it’s platinum that’s the issue.
If it doesn’t, your Pokémon are the issue.
Let me know the results of these tests. If it’s not your system, not your Gen 5, not your Pokémon, then it’s 100% your platinum. Can you confirm the platinum is authentic?