That's a great question. If you check the repository URL for this NFT, which is the code in
FunC, Telemint, you'll see a line of code that reads
throw_unless(err::not_enough_funds, bid >= initial_min_bid);*1.
This line means that you need more funds in the NFT itself to trigger this kind of transaction in practice. In other words, "not enough funds" means that you should replenish the balance of the NFT smart contract so that there is more than 💎1.