Transaction not found using cast publish

[18a6]

1. I wrote this function in go-ethereum to return a raw transaction:

func createTx(c *ethclient.Client) (rawTxnHex string) {
    from := common.HexToAddress("0xf39Fd6e51aad88F6F4ce6aB8827279cffFb92266")
    nonce, _ := c.PendingNonceAt(context.Background(), from)
    suggestedGasPrice, _ := c.SuggestGasPrice(context.Background())
    gasPrice := new(big.Int).Mul(suggestedGasPrice, big.NewInt(10))
    gas := uint64(30000000)
    to := common.HexToAddress("0x976EA74026E726554dB657fA54763abd0C3a0aa9")
    value := big.NewInt(1000000000000)
    data := []byte("hoy--")

    var inner types.TxData = &types.LegacyTx{
        Nonce:    nonce,     // nonce of sender account
        GasPrice: gasPrice,  // wei per gas
        Gas:      gas,       // gas limit
        To:       &to,       // nil means contract creation
        Value:    value,     // wei amount
        Data:     data,      // contract invocation input data
    }
    tx := types.NewTx(inner)
    SEPOLIA_ID := big.NewInt(11155111)
    privateKey, err := crypto.HexToECDSA(utils.GetKey("PRIVATE_KEY"))
    if err != nil {
        log.Fatal(err)
    }
    signedTxn, err := types.SignTx(tx, types.NewLondonSigner(SEPOLIA_ID), privateKey)
    if err != nil {
        log.Fatal(err)
    }
    rawTxnBytes, err := rlp.EncodeToBytes(signedTxn)
    if err != nil {
        log.Fatal(err)
    }
    rawTxnHex = hex.EncodeToString(rawTxnBytes)
    fmt.Println("transaction created:", rawTxnHex)

    return rawTxnHex
}

2. I run a sepolia fork using anvil --fork-url https://sepolia.infura.io/v3/$PRIVATE_KEY
3. I run cast publish --rpc-url $RPC_URL $RAW_TX_HEX but always get this error: tx $TX_HASH not found

What am I missing here?