What's wrong, what does that exit code means?

jettons_amount = transaction["jettonsAmount"]
to_address = transaction["toAddress"]
seqno = get_seqno(wallet.address.to_string()) or 0

body = (
begin_cell()
.store_uint(0xF8A7EA5, 32)
.store_uint(0, 64)
.store_coins(int(1000 * jettons_amount))
.store_address(Address(to_address))
.store_address(wallet.address)
.store_bit(False)
.store_coins(0)
.end_cell()
)

# Create transfer message
query = wallet.create_transfer_message(
to_addr="EQCq8ZnUcYtLHLyVCU6NbjNRyCB7mb-NwzF-Zc0RHnEUh1JA",
amount=to_nano(4, "ton"),
seqno=int(seqno),
payload=body,
)
message: Cell = query["message"]

boc = bytes_to_base64(message.to_boc(False))
client.send_boc(boc)