We are using the ERC1155 NFT standard. Please make sure, that the wallet you are using, does fully support this standard prior to processing the transfer. As of now for instance, MetaMask does not fully support these tokens. The transfer does technically work but you cannot see the NFT anywhere in the wallet. The mobile version seems to work better but the browser extension version seems to not show them at the moment at all.
Please always refer to your wallet provider in such cases.