Why outputs' spendable and solvable are false? I noticed a transaction whose spendable and solvable are both false, what does this mean and why?

 {
    "txid": "c940241a0ef626e865e2004bc120536fb7868d510115e923c76d5e658a97f6d5",
    "vout": 0,
    "address": "mnbFFLXUqTPBweLm6w1GA2ZAJQbrTndEGC",
    "account": "",
    "scriptPubKey": "76a9144d98b2350032c849ac6e6e7ad0eb88e00fd7fbff88ac",
    "amount": 1.10000000,
    "confirmations": 132,
    "spendable": false,
    "solvable": false
},


Is this means this utxo is invalid somehow so cannot spend it?

Also, this is on testnet.
The listunspent rpc call returns all unspent transaction outputs (UTXOs) tracked by this wallet. This includes the UTXOs that can be spent by this wallet, but also UTXOs that belong to watch-only addresses tracked by this wallet.

When spendable is false, this wallet does not have the private key to spend the UTXO. This is e.g. the case for watch-only addresses.

When solvable is false, the wallet does not know how to spend the UTXO, regardless of whether it has the corresponding private keys.