Getting a negative token id when buying nft

Moralis General
#1

Hello,
I am facing an issue when I buy a nft through the Shop which I created by following the steps mentioned in the official tutorial by Moralis Web3 channel on youtube. I am getting a negative token ID, is this a bug or is this a functionality by Morlais? Please explain.

Youtube Tutorial

#2

Which contract address (and chain) are you using? What does the tokenId look like and what does your function call (buyItem) look like?

#3

Hello,
My contract address is : 0x4cec0a85A8F8CAe8c340E59Ae1a91Ef0300F6047
Chain : Mumbai
buy Item function : function buyItem(uint256 _tokenId, string memory _tokenUrl, bytes memory data) public /onlyOwner/{

    //IMPORTANT Implement own security (set ownership to users). Not production ready contract
    
    _tokenUrls[_tokenId] = _tokenUrl;
    _mint(msg.sender, _tokenId, 1, data);
}

I am getting token ID : -21, -11, 11, etc. also I am getting same token ID for some items.

I have not made any changes to the buyItem function.
What is the problem here?
Please help!!!

#4

Everything seems ok with that contract’s events with tokenIds of 235 and 11 used. Can you screenshot these negative tokenIds you’re getting - it may be an issue with the Unity project.

Make sure your code matches the tutorial repo and any changes made in the video.

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