Question: I'm getting this error when I try to run my app, I'm using all the same dependencies that I always use so I'm very baffled by this.

> 
> Warn in
> 
> 
> in ./assets/css/style.css
> 
> 
> Module Warning (from ./node\_modules/postcss-loader/src/index.js):  
> 
> (13:3) start value has mixed support, consider using flex-start
> instead
> friendly-errors 18:06:28 @ ./assets/css/style.css @ ./.nuxt/App.js
> @ ./.nuxt/index.js @ ./.nuxt/client.js @ multi eventsource-polyfill
> webpack-hot-middleware/client?reload=true&timeout=30000&ansiColors=&overlayStyles=&path=%2F\_\_webpack\_hmr%2Fclient&name=client
> ./.nuxt/client.js
> 
> 
> 

what should i do?

Answer: 
If the `signUp` method is blocking (i.e. it returns once the signup is finished), your code should work as expected. So I suspect it is asynchronous.

In that case, on top of using a boolean, you could also use a `CountDownLatch` to wait until the async method completes:

```
AtomicBoolean success = new AtomicBoolean(false);
CountDownLatch done = new CountDownLatch(1);
Amplify.Auth.signUp(
        email,
        password,
        AuthSignUpOptions.builder().userAttribute(AuthUserAttributeKey.email(), email).build(),
        result -> { success.set(true); done.countDown(); },
        error -> { Log.e("AuthQuickStart", "Sign up failed", error); done.countDown(); }
);
done.await(); //you may want to add a timeout here
Log.d("success", String.valueOf(success.get()));

```
An `AtomicBoolean` variable (`success`) is used correctly. Most probably,

```
Log.d("success", String.valueOf(success.get()));

```

is called before

```
result -> success.set(true)

```

because of asynchronous execution of callback. Alternatively result callback is not called at all.

**You can test it by changing callback body to:**

```
 result -> {
     Log.d("callback test", "callback start");
     result -> success.set(true);
     Log.d("callback test", "callback end");
}

```

If `"callback test"` doesn't appear in the logs then callback is not called.  

If `"callback test"` appear after `"success"` then callback body is called after `Log.d("success", String.valueOf(success.get()));` due to asynchronous execution.