Android Auto Backup Not Working

I have followed the guidelines for configuring auto backup for android here.

Here's my backupscheme.xml

<?xml version="1.0" encoding="utf-8"?>
<full-backup-content >
    <include domain="database" path="device_info.db"/>
</full-backup-content

My manifest contains

<application
android:allowBackup="true"
android:icon="@drawable/time_machine_launcher"
android:label="@string/app_name"
android:theme="@style/AppTheme" 
android:name="com.friscosoftware.timelytext.TimelyTextApplicationBasic"
android:fullBackupContent="@xml/backupscheme" 
> 

My targetSdkVersion=23. For testing, I have enabled backup logging using

adb shell setprop log.tag.BackupXmlParserLogging VERBOSE

I initialized backup using

adb shell bmgr run

and I performed backup using

adb shell bmgr fullbackup myPackageName

. The latter command gave me this in response,

Performing full transport backup

I attempted restore using

adb shell bmgr restore myPackageName and got this in response

Unable to restore package myPackageName done

I'm not sure why it's failing. Any suggestions? Thanks.