为什么 TextInputEditText 不能正常工作？

<?xml version="1.0" encoding="utf-8"?>

<android.support.design.widget.TextInputLayout
    android:id="@+id/textInputLayout"
    android:layout_width="0dp"
    android:layout_height="wrap_content"
    android:layout_marginTop="32dp"
    android:background="@android:color/white"
    android:padding="8dp"
    android:textColorHint="@color/color_text_description"
    app:layout_constraintEnd_toEndOf="parent"
    app:layout_constraintHorizontal_bias="0.5"
    app:layout_constraintStart_toStartOf="parent"
    app:layout_constraintTop_toBottomOf="@+id/textView2"
    tools:ignore="MissingConstraints">

    <android.support.design.widget.TextInputEditText
        android:id="@+id/etEmail"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:gravity="center"
        android:inputType="textEmailAddress"
        android:imeOptions="actionNext"
        android:hint="@string/email_address"
        app:backgroundTint="@android:color/transparent"/>
</android.support.design.widget.TextInputLayout>

<TextView
    android:id="@+id/textView"
    android:layout_width="0dp"
    android:layout_height="1px"
    android:background="@android:color/transparent"
    app:layout_constraintEnd_toEndOf="parent"
    app:layout_constraintHorizontal_bias="0.5"
    app:layout_constraintStart_toStartOf="parent"
    app:layout_constraintTop_toBottomOf="@+id/textInputLayout"/>

<android.support.design.widget.TextInputLayout
    android:id="@+id/textInputLayoutPass"
    android:layout_width="0dp"
    android:layout_height="wrap_content"
    android:background="@android:color/white"
    android:padding="8dp"
    android:textColorHint="@color/color_text_description"
    app:layout_constraintEnd_toEndOf="parent"
    app:layout_constraintHorizontal_bias="0.5"
    app:layout_constraintStart_toStartOf="parent"
    app:layout_constraintTop_toBottomOf="@+id/textView"
    tools:ignore="MissingConstraints">

    <android.support.design.widget.TextInputEditText
        android:id="@+id/etPass"
        android:imeOptions="actionDone"
        android:inputType="textPassword"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:gravity="center"
        android:hint="@string/password"
        app:backgroundTint="@android:color/transparent"/>
</android.support.design.widget.TextInputLayout>

<ImageView
    android:id="@+id/imageView4"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_marginTop="24dp"
    app:layout_constraintEnd_toEndOf="parent"
    app:layout_constraintHorizontal_bias="0.5"
    app:layout_constraintStart_toStartOf="parent"
    app:layout_constraintTop_toTopOf="parent"
    app:srcCompat="@drawable/slife_logo"/>

<TextView
    android:id="@+id/textView2"
    android:layout_width="wrap_content"
    android:layout_height="27dp"
    android:layout_marginTop="8dp"
    android:text="Conscious life here and now"
    android:textColor="@color/color_text_description"
    android:textSize="16sp"
    app:layout_constraintEnd_toEndOf="parent"
    app:layout_constraintHorizontal_bias="0.5"
    app:layout_constraintStart_toStartOf="parent"
    app:layout_constraintTop_toBottomOf="@+id/imageView4"/>

<TextView
    android:id="@+id/txtForgottenPas"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_marginTop="8dp"
    android:fontFamily="@font/roboto_medium"
    android:text="FORGOTTEN PASSWORD?"
    android:textColor="@color/color_text"
    app:layout_constraintEnd_toEndOf="parent"
    app:layout_constraintHorizontal_bias="0.5"
    app:layout_constraintStart_toStartOf="parent"
    app:layout_constraintTop_toBottomOf="@+id/textInputLayoutPass"/>

<Button
    android:id="@+id/btnLogin"
    android:layout_width="0dp"
    android:layout_height="60dp"
    android:layout_marginEnd="8dp"
    android:layout_marginStart="8dp"
    android:layout_marginTop="64dp"
    android:text="LOG IN"
    android:enabled="false"
    android:background="@drawable/btn_auth"
    android:textColor="@color/text_auth"
    app:layout_constraintEnd_toEndOf="parent"
    app:layout_constraintHorizontal_bias="0.5"
    app:layout_constraintStart_toStartOf="parent"
    app:layout_constraintTop_toBottomOf="@+id/txtForgottenPas"/>

<TextView
    android:id="@+id/txtRegistration"
    android:layout_width="wrap_content"
    android:layout_height="0dp"
    android:layout_marginTop="24dp"
    android:fontFamily="@font/roboto_medium"
    android:text="NEW USER/REGISTRATION"
    android:textColor="@color/color_text"
    app:layout_constraintEnd_toEndOf="parent"
    app:layout_constraintHorizontal_bias="0.5"
    app:layout_constraintStart_toStartOf="parent"
    app:layout_constraintTop_toBottomOf="@+id/btnLogin"/>

正如您在图片中看到的，电子邮件和密码这两个字段是相同的，但由于某种原因，密码字段无法正常工作。尽管在代码中一切都是一样的。问题是什么？如何删除下划线动画。？