diff --git a/twidere/src/main/kotlin/org/mariotaku/twidere/activity/SignInActivity.kt b/twidere/src/main/kotlin/org/mariotaku/twidere/activity/SignInActivity.kt
index 14c3b072a..7c939ace1 100644
--- a/twidere/src/main/kotlin/org/mariotaku/twidere/activity/SignInActivity.kt
+++ b/twidere/src/main/kotlin/org/mariotaku/twidere/activity/SignInActivity.kt
@@ -51,7 +51,10 @@ import android.widget.Toast
 import kotlinx.android.synthetic.main.activity_sign_in.*
 import kotlinx.android.synthetic.main.dialog_expandable_list.*
 import kotlinx.android.synthetic.main.dialog_login_verification_code.*
+import nl.komponents.kovenant.CancelException
+import nl.komponents.kovenant.Deferred
 import nl.komponents.kovenant.combine.and
+import nl.komponents.kovenant.deferred
 import nl.komponents.kovenant.task
 import nl.komponents.kovenant.ui.alwaysUi
 import nl.komponents.kovenant.ui.failUi
@@ -409,7 +412,7 @@ class SignInActivity : BaseActivity(), OnClickListener, TextWatcher,
             result.addAccount(am, preferences[randomizeAccountNameKey])
             Analyzer.log(SignIn(true, accountType = result.type,
                     credentialsType = apiConfig.credentialsType,
-                    officialKey = result.extras?.official ?: false))
+                    officialKey = result.extras?.official == true))
             finishSignIn()
         }
     }
@@ -461,6 +464,10 @@ class SignInActivity : BaseActivity(), OnClickListener, TextWatcher,
         }
     }
 
+    internal fun dismissSignInProgressDialog() {
+        dismissDialogFragment(FRAGMENT_TAG_SIGN_IN_PROGRESS)
+    }
+
     private fun showLoginTypeChooser() {
         executeAfterFragmentResumed {
             val fm = it.supportFragmentManager
@@ -681,7 +688,7 @@ class SignInActivity : BaseActivity(), OnClickListener, TextWatcher,
 
     internal class InputLoginVerificationDialogFragment : BaseDialogFragment() {
 
-        var callback: SignInTask.InputLoginVerificationCallback? = null
+        var deferred: Deferred<String?, Exception>? = null
         var challengeType: String? = null
 
         override fun onCreateDialog(savedInstanceState: Bundle?): Dialog {
@@ -696,15 +703,15 @@ class SignInActivity : BaseActivity(), OnClickListener, TextWatcher,
         }
 
         override fun onCancel(dialog: DialogInterface?) {
-            callback?.challengeResponse = null
+            deferred?.reject(CancelException())
         }
 
         private fun performVerification(dialog: Dialog) {
-            callback?.challengeResponse = dialog.editVerificationCode.string
+            deferred?.resolve(dialog.editVerificationCode.string)
         }
 
         private fun cancelVerification(dialog: Dialog) {
-            callback?.challengeResponse = null
+            deferred?.reject(CancelException())
         }
 
         private fun onDialogShow(dialog: Dialog) {
@@ -1040,46 +1047,35 @@ class SignInActivity : BaseActivity(), OnClickListener, TextWatcher,
 
         internal inner class InputLoginVerificationCallback : OAuthPasswordAuthenticator.LoginVerificationCallback {
 
-            var isChallengeFinished: Boolean = false
-
-            var challengeResponse: String? = null
-                set(value) {
-                    isChallengeFinished = true
-                    field = value
-                }
-
             override fun getLoginVerification(challengeType: String): String? {
                 // Dismiss current progress dialog
                 publishProgress(Runnable {
-                    activityRef.get()?.dismissDialogFragment(SignInActivity.FRAGMENT_TAG_SIGN_IN_PROGRESS)
+                    activityRef.get()?.dismissSignInProgressDialog()
                 })
+                val deferred = deferred<String?, Exception>()
                 // Show verification input dialog and wait for user input
                 publishProgress(Runnable {
                     val activity = activityRef.get() ?: return@Runnable
-                    activity.executeAfterFragmentResumed { activity ->
-                        val sia = activity as SignInActivity
+                    activity.executeAfterFragmentResumed {
+                        val sia = it as SignInActivity
                         val df = InputLoginVerificationDialogFragment()
                         df.isCancelable = false
-                        df.callback = this@InputLoginVerificationCallback
+                        df.deferred = deferred
                         df.challengeType = challengeType
                         df.show(sia.supportFragmentManager, "login_challenge_$challengeType")
                     }
                 })
-                while (!isChallengeFinished) {
-                    // Wait for 50ms
-                    try {
-                        Thread.sleep(50)
-                    } catch (e: InterruptedException) {
-                        // Ignore
-                    }
 
+                return try {
+                    deferred.promise.get()
+                } catch (e: CancelException) {
+                    throw MicroBlogException(e)
+                } finally {
+                    // Show progress dialog
+                    publishProgress(Runnable {
+                        activityRef.get()?.showSignInProgressDialog()
+                    })
                 }
-                // Show progress dialog
-                publishProgress(Runnable {
-                    val activity = activityRef.get() ?: return@Runnable
-                    activity.showSignInProgressDialog()
-                })
-                return challengeResponse
             }
 
         }
@@ -1253,6 +1249,6 @@ class SignInActivity : BaseActivity(), OnClickListener, TextWatcher,
                 else -> null
             }
 
-        }
+    }
 
 }
diff --git a/twidere/src/main/kotlin/org/mariotaku/twidere/util/OAuthPasswordAuthenticator.kt b/twidere/src/main/kotlin/org/mariotaku/twidere/util/OAuthPasswordAuthenticator.kt
index 31b525587..942a82546 100644
--- a/twidere/src/main/kotlin/org/mariotaku/twidere/util/OAuthPasswordAuthenticator.kt
+++ b/twidere/src/main/kotlin/org/mariotaku/twidere/util/OAuthPasswordAuthenticator.kt
@@ -328,6 +328,7 @@ class OAuthPasswordAuthenticator(
     }
 
     interface LoginVerificationCallback {
+        @Throws(MicroBlogException::class)
         fun getLoginVerification(challengeType: String): String?
     }