ERC721 Contract Cant Verify due to Source "@openzeppelin/contracts/token/ERC721/ERC721.sol" not found: File import callback not supported

Hello, Im trying to verify my contract but seem to be having a pit of a problem.

Seems to be having problem with the imports. How can I solve this?

can anyone help?

Replace each import statement with the actual contents of the imported file.

I manage to solve it

I just flatten my codes from remix and copy paste it.