E / AndroidRuntime: FATAL EXCEPTION: main и Coroutine, Retrofit2

Я только начал изучать котлин, и мое первое приложение использует Retrofit2 и Coroutine, но есть проблема. У меня есть некоторая ошибка, но с помощью Coroutine трассировка стека очень бедна информацией. Может, кто-то найдет ошибку или знает, как сделать трассировку стека более информативной.

ApiService:

const val API_KEY = "Bcae2032bb596c73b10bdab625c037da"

interface CurrencyApi {

//https://api.currencystack.io/currency?base=USD&target=EUR&apikey=Bcae2032bb596c73b10bdab625c037da

@GET("currency")
fun getCurrentCurrency(
    @Query("base") base: String,
    @Query("target") target: String
): Deferred<Currency>

companion object {
    operator fun invoke(): CurrencyApi {
        val requestInterceptor = Interceptor { chain ->

            val url = chain.request()
                .url()
                .newBuilder()
                .addQueryParameter("key", API_KEY)
                .build()
            val request = chain.request()
                .newBuilder()
                .url(url)
                .build()

            return@Interceptor chain.proceed(request)
        }

        val okHttpClient = OkHttpClient.Builder()
            .addInterceptor(requestInterceptor)
            .build()

        return Retrofit.Builder()
            .client(okHttpClient)
            .baseUrl("https://api.currencystack.io/")
            .addCallAdapterFactory(CoroutineCallAdapterFactory())
            .addConverterFactory(GsonConverterFactory.create())
            .build()
            .create(CurrencyApi::class.java)
    }
}

Мероприятия:

 class MainActivity : AppCompatActivity(), AdapterView.OnItemSelectedListener {


override fun onCreate(savedInstanceState: Bundle?) {
    super.onCreate(savedInstanceState)
    val binding: ActivityMainBinding = DataBindingUtil.setContentView(this, R.layout.activity_main)
    val model = ViewModelProviders.of(this).get(MainViewModel::class.java)

    val apiService = CurrencyApi()

    GlobalScope.launch(Dispatchers.Main) {
        val currency = apiService.getCurrentCurrency("PLN", "EUR").await()
        return@launch try {
            text_view_test.text = currency.toString()
        } catch (e: Exception) {

        }
    }

Logcat:

E/AndroidRuntime: FATAL EXCEPTION: main Process: com.example.daniellachacz.currencyconverter, PID: 10924 retrofit2.HttpException: HTTP 400 at com.jakewharton.retrofit2.adapter.kotlin.coroutines.CoroutineCallAdapterFactory$BodyCallAdapter$adapt$2.onResponse(CoroutineCallAdapterFactory.kt:104) at retrofit2.OkHttpCall$1.onResponse(OkHttpCall.java:123) at okhttp3.RealCall$AsyncCall.execute(RealCall.java:153) at okhttp3.internal.NamedRunnable.run(NamedRunnable.java:32) at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1113) at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:588) at java.lang.Thread.run(Thread.java:818)