AAPT : 오류 : 형식이 잘못되었습니다 (잘못된 토큰).

다음 XML을 사용하여 응용 프로그램에서 작업 중입니다. 이것은 내 로그인 조각의 XML입니다. 그러나 프로젝트를 정리 / 빌드하려고하면 다음 오류가 발생합니다.

오류 : XML 구문 분석 오류 : 형식이 잘못되었습니다 (잘못된 토큰).

<?xml version="1.0" encoding="utf-8"?>
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
xmlns:app="http://schemas.android.com/apk/res-auto"
tools:context=".SignInFragment"
android:background="@drawable/gradient_color">
<androidx.constraintlayout.widget.ConstraintLayout
android:layout_width="match_parent"
android:layout_height="match_parent">
<ImageButton
android:id="@+id/sign_up_close_btn"
android:layout_width="50dp"
android:layout_height="50dp"
android:background="@android:color/transparent"
android:padding="16dp"
android:src="@drawable/ic_cancel"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="1.0"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent" />
<ImageView
android:id="@+id/imageView"
android:layout_width="254dp"
android:layout_height="182dp"
android:src="@mipmap/ic_launcher_foreground"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.496"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintVertical_bias="0.16000003" />
<EditText
android:id="@+id/sign_in_email"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_marginStart="16dp"
android:layout_marginLeft="16dp"
android:layout_marginTop="32dp"
android:layout_marginEnd="16dp"
android:layout_marginRight="16dp"
android:backgroundTint="#70FFFFFF"
android:textColor="@color/colorAccent"
android:ems="10"
android:hint="@string/hint_email"
android:inputType="textEmailAddress"
android:textColorHint="#70FFFFFF"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="@+id/imageView" />
<EditText
android:id="@+id/sign_in_pass"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_marginStart="16dp"
android:layout_marginLeft="16dp"
android:layout_marginTop="32dp"
android:layout_marginEnd="16dp"
android:layout_marginRight="16dp"
android:backgroundTint="#70FFFFFF"
android:textColor="@color/colorAccent"
android:ems="10"
android:hint="@string/hint_pass"
android:inputType="textPassword"
android:textColorHint="#70FFFFFF"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="@+id/sign_in_email" />
<TextView
android:id="@+id/sign_in_forgot_pass"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginStart="4dp"
android:layout_marginLeft="4dp"
android:text="@string/forg_pass"
android:textColor="@color/colorAccent"
app:layout_constraintStart_toStartOf="@+id/sign_in_pass"
app:layout_constraintTop_toBottomOf="@+id/sign_in_pass" />
<Button
android:id="@+id/sign_in_btn"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_marginStart="16dp"
android:layout_marginLeft="16dp"
android:layout_marginEnd="16dp"
android:layout_marginRight="16dp"
android:background="@color/colorPrimary"
android:text="@string/btn_In"
android:textAllCaps="false"
android:textColor="@color/colorAccent"
android:textSize="16sp"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.0"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="@+id/sign_in_forgot_pass"
app:layout_constraintVertical_bias="0.47000003" />
<TextView
android:id="@+id/textView2"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginTop="16dp"
android:text="@string/or"
android:textColor="@color/colorAccent"
app:layout_constraintBottom_toTopOf="@+id/tv_dont_have_an_account"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.498"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="@+id/sign_in_btn"
app:layout_constraintVertical_bias="0.0" />
<TextView
android:id="@+id/tv_dont_have_an_account"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginBottom="24dp"
android:text="@string/text1"
android:textColor="@color/colorAccent"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent" />
<View
android:id="@+id/divider"
android:layout_width="100dp"
android:layout_height="1dp"
android:layout_marginEnd="16dp"
android:layout_marginRight="16dp"
android:background="@color/colorAccent"
app:layout_constraintBottom_toBottomOf="@+id/textView2"
app:layout_constraintEnd_toStartOf="@+id/textView2"
app:layout_constraintTop_toTopOf="@+id/textView2" />
<View
android:id="@+id/divider2"
android:layout_width="100dp"
android:layout_height="1dp"
android:layout_marginStart="16dp"
android:layout_marginLeft="16dp"
android:background="@color/colorAccent"
app:layout_constraintBottom_toBottomOf="@+id/textView2"
app:layout_constraintStart_toEndOf="@+id/textView2"
app:layout_constraintTop_toTopOf="@+id/textView2" />
<ProgressBar
android:id="@+id/sign_in_progress_bar"
style="?android:attr/progressBarStyle"
android:layout_width="30dp"
android:layout_height="30dp"
android:visibility="invisible"
app:layout_constraintBottom_toTopOf="@+id/sign_in_btn"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="@+id/sign_in_pass" />
</>
</FrameLayout>

무슨 뜻일까요? 내가 뭘 잘못 했어? 정말 걱정이됩니다. 내 코드를 여러 번 살펴 봤지만 오류를 찾지 못했습니다.