Recently, we added a notification modal that lets you know something that is showing in your profile page > My NFT's tab is listed in another smart contract.

More than likely, this means it's staked with another platform or perhaps has a loan for it.

To be able to list on our smart contract, you first need to remove it from that contract, then you can list it.

If you have any questions with this, feel free to open a support ticket in our discord and we can help you take a look into this.