Bitcoin uses the UTXO model (Unspent Transaction Output), meaning your balance is stored in individual outputs rather than a single total. Some outputs contain Ordinals inscriptions, which may be valuable and which you don't want to accidentally send.
How it works
If your wallet contains Ordinals, Phantom shows their value in your total balance under Tokens. However, the Bitcoin tied to these UTXOs is excluded from your sendable balance.
This means your total balance may look correct, but your sendable balance may show as $0 if all your Bitcoin is tied to Ordinals.
Note: Looking for your BRC-20 tokens? Phantom no longer supports BRC-20s. You can still view and manage them by connecting your Phantom wallet to Magic Eden or another NFT marketplace that supports BRC-20s.
What to do to send protected Bitcoin
To manually control which UTXOs are included in a transaction, import your recovery phrase into an external wallet like Sparrow. See Send Bitcoin using Sparrow wallet.