Websocket Web3j cannot subscribe

Hello,
I have been trying to use websocket protocol with web3j without any success so far:
I am integrating the websocket flow by baby steps
web3jSocketConnection
.transactionFlowable()
.doOnSubscribe(
subscription -> log.info(“Subscribe to newly transactions confirmed on the blockchain.”))
.filter(transaction-> transaction.getTo().equals(supplierCompletableFuture.get().get().getAddress()))
.subscribe(
transaction-> log.info(“Transaction from, to, gasPrice {}, {}, {}”, transaction.getFrom(), transaction.getTo(), transaction.getGasPrice()),
throwable -> log.error(“Could not subscribe to block notifications: {}”, throwable.getMessage())
);
Here is the link to the repo

Could you also provide the full error responses you are receiving?