NullPointerException в Android 7.0

Fatal Exception: java.lang.NullPointerException: Attempt to invoke virtual method 'void android.support.v4.app.Fragment.setNextAnim(int)' on a null object reference
   at android.support.v4.app.BackStackRecord.executeOps(BackStackRecord.java:760)
   at android.support.v4.app.FragmentManagerImpl.executeOps(FragmentManager.java:2415)
   at android.support.v4.app.FragmentManagerImpl.executeOpsTogether(FragmentManager.java:2200)
   at android.support.v4.app.FragmentManagerImpl.optimizeAndExecuteOps(FragmentManager.java:2153)
   at android.support.v4.app.FragmentManagerImpl.execPendingActions(FragmentManager.java:2063)
   at android.support.v4.app.FragmentManagerImpl.popBackStackImmediate(FragmentManager.java:831)
   at android.support.v4.app.FragmentManagerImpl.popBackStackImmediate(FragmentManager.java:791)
   at android.support.v4.app.FragmentActivity.onBackPressed(FragmentActivity.java:173)
   at com.knowledgecity.common.BaseActivity.onBackPressed(BaseActivity.java:131)
   at com.knowledgecity.activity.MainActivity.onBackPressed(MainActivity.java:322)
   at android.app.Activity.onKeyUp(Activity.java:2854)
   at android.view.KeyEvent.dispatch(KeyEvent.java:3346)

Данная ошибка появляется в Android 7.0. При просмотре видео. В остальных версиях все нормально. В чем проблема?