Thread gets blocked in thenAccept but works in thenAcceptAsync

Question

I am using Helidon WebClient to do API calls, I have struck upon a certain use case, I am pasting a demo of the use case.

        var request = webClient.get()
                .path("/api/users?page=2")
                .request(String.class)
                .thenAccept(res -> {
                    printThreadId("firstreq");
                    
                    System.out.println(res);
                    
                    var res2 = webClient.get()
                            .path("/api/users?page=2")
                            .request(String.class)
                            .await();

                    System.out.println(res2);

                    cf.complete(null);
                });

The problem is thread is getting blocked for endless time after the res2 call.

The solution was to use thenAcceptAsync instead of thenAccept. But, I am not able to understand, why this is the case?