UnityAds crashes in certain Android device

UnityAds crashes when it showed in certain Android device. Unity ver is 4.6.9 but I tried in version 5.3.3, it crashed too.

Device: ・GALAXY S5（SAMSUNG） Android 5.0 ・AQUOS PHONE Xx mini（SHARP） Android 4.2.2

this is my crashes log in AQUOS PHONE Xx mini

 I/UnityAds(22549): com.unity3d.ads.android.UnityAds.canShow() (line:278) :: Unity Ads is ready to show ads
 I/UnityAds(22549): com.unity3d.ads.android.UnityAds.show() (line:187) :: Launching ad from "Rewarded video ad placement", options: {"disableBackButtonForSeconds":30,"enabled":true,"openAnimated":false,"incentivised":true,"deleted":false,"useDeviceOrientationForVideo":false,"allowVideoSkipInSeconds":-1,"defaultRewardItem":{"picture":"https:\/\/static.applifier.com\/unityads\/unityicon_62.png","key":"default","name":"Default reward item"},"id":"rewardedVideoZone","allowClientOverrides":["noOfferScreen","openAnimated","muteVideoSounds","useDeviceOrientationForVideo"],"default":false,"allowSkipVideoInSeconds":-1,"name":"Rewarded video ad placement","muteVideoSounds":false,"noOfferScreen":true,"rewardItems":[{"picture":"https:\/\/static.applifier.com\/unityads\/unityicon_62.png","key":"default","name":"Default reward item"}]}
 I/ActivityManager(  763): START u0 {flg=0x10010000 cmp=jp.tgl.UnityAds/com.unity3d.ads.android.view.UnityAdsFullscreenActivity} from pid 22549
 I/dun_service(  328): received event(DUN_EVENT_USB_UNPLUG) in state(DUN_STATE_USB_UNPLUG)
 V/Sensors (  763): setDelay : 1000000000 ns, (1.00 Hz)
 I/ActivityManager(  763): Config changes=1480 {1.0 ?mcc?mnc ja_JP ldltr sw360dp w598dp h335dp 480dpi nrml land finger -keyb/v/h -nav/h s.208}
 I/dun_service(  328): received event(DUN_EVENT_USB_UNPLUG) in state(DUN_STATE_USB_UNPLUG)
 E/MediaPlayer(22549): Uri is <URI SUPPRESSED>
 D/PhoneApp( 1108): updateProximitySensorMode: state = IDLE
 D/PhoneApp( 1108): updateProximitySensorMode: lock already released.
 I/dun_service(  328): received event(DUN_EVENT_USB_UNPLUG) in state(DUN_STATE_USB_UNPLUG)
 I/Web Console(22549): Hiding all views at http://static.applifier.com/impact/webview/production/impact/index.html?version=ba7d7e41392278d8549ef6e940bfb65873846403:8715
 I/Web Console(22549): Showing: none at http://static.applifier.com/impact/webview/production/impact/index.html?version=ba7d7e41392278d8549ef6e940bfb65873846403:8713
 I/ActivityManager(  763): Displayed jp.tgl.UnityAds/com.unity3d.ads.android.view.UnityAdsFullscreenActivity: +316ms
 I/Web Console(22549): Resize handler called at http://static.applifier.com/impact/webview/production/impact/index.html?version=ba7d7e41392278d8549ef6e940bfb65873846403:8732
 W/AwesomePlayer(11605): Trying to create tunnel player mIsTunnelAudio 0,                         LPAPlayer::objectsAlive 0,                         TunnelPlayer::mTunnelObjectsAlive = 0,                        (mAudioPlayer == NULL) 1
 D/MediaPlayer(22549): start() mUri is <URI SUPPRESSED>
 D/ALSAStreamOps(11605): setParameters(): keyRouting with device 0x2
 D/AudioHardwareALSA(11605): device = 0x2,mCurDevice 0x2
 E/AudioHardwareALSA(11605): int* android_audio_legacy::AudioHardwareALSA::getCallStateForVSID(uint32_t): Invalid vsid:0
 E/AudioHardwareALSA(11605): bool android_audio_legacy::AudioHardwareALSA::routeCall(int, int, uint32_t)(): Error, mCurCallState=0x0 is NULL
 
 D/alsa_ucm(11605): snd_use_case_set(): uc_mgr 0x42984120 identifier _enadev value Speaker
 D/alsa_ucm(11605): Set mixer controls for HiFi enable 1
 D/alsa_ucm(11605): Setting mixer control: SLIMBUS_0_RX Audio Mixer MultiMedia1, value: 1
 D/ALSADevice(11605): switchDevice: mCurTxUCMDevivce Ambient mCurRxDevDevice Speaker
 D/AudioHardwareALSA(11605): setVoiceVolume(0.800000)
 D/AudioHardwareALSA(11605): Setting FM volume to 2023 (available range is 0 to 0x2000)
 W/MediaPlayer(22549): info/warning (3, 0)
 I/MediaPlayer(22549): Info (3,0)
 I/dun_service(  328): received event(DUN_EVENT_USB_UNPLUG) in state(DUN_STATE_USB_UNPLUG)
 I/WindowState(  763): WIN DEATH: Window{42ce00d0 u0 jp.tgl.UnityAds/com.unity3d.player.UnityPlayerActivity}
 I/ActivityManager(  763): Process jp.tgl.UnityAds (pid 22549) has died.
 W/TimedEventQueue(11605): Event 13 was not found in the queue, already cancelled?
 W/ActivityManager(  763): Force removing ActivityRecord{468e4020 u0 jp.tgl.UnityAds/com.unity3d.ads.android.view.UnityAdsFullscreenActivity}: app died, no saved state
 I/WindowState(  763): WIN DEATH: Window{42c6d6e0 u0 SurfaceView}
 I/WindowState(  763): WIN DEATH: Window{42c582a8 u0 jp.tgl.UnityAds/com.unity3d.ads.android.view.UnityAdsFullscreenActivity}
 W/WindowManager(  763): Force-removing child win Window{42c6d6e0 u0 SurfaceView EXITING} from container Window{42c582a8 u0 jp.tgl.UnityAds/com.unity3d.ads.android.view.UnityAdsFullscreenActivity}
 I/ActivityManager(  763): Start proc jp.tgl.UnityAds for activity jp.tgl.UnityAds/com.unity3d.player.UnityPlayerActivity: pid=22979 uid=10204 gids={50204, 1015, 1023, 3003, 1028}
 W/BufferQueue(  267): [SurfaceView] cancelBuffer: BufferQueue has been abandoned!