Mintable ERC20 Token Smart Contarct

Question

I'm editing the ERC20 Contract from @OpenZeppelin to make it mintable you can see my progress here:

https://github.com/GameBully2K/Blockchain/blob/main/MintableERC20Token.sol

Now I'm facing a problem with the mint (line 685) function where I receive

Internal JSON-RPC error. { "code": -32000, "message": "execution reverted" }