[Android Apps and Games] Timmmmaaahh!:
That is a good question but at the same time completely pointless. You see, if there is no log, it simply didn't happen. So what you meant to say was:

VR doesn't work! Here's my fancy pants log:

02-04 08:00:41.307 1137 4111 I ActivityTaskManager: Config changes=20000480 {1.0 0 206mcc30mnc [en_GB,en_US,nl_BE] ldltr sw454dp w951dp h421dp 380dpi nrml long hdr widecg land night force dark=0 finger -keyb/v/h -nav/h winConfig={ mBounds=Rect(0, 0 - 2340, 1080) mAppBounds=Rect(80, 0 - 2340, 1080) mWindowingMode=fullscreen mDisplayWindowingMode=fullscreen mActivityType=undefined mAlwaysOnTop=undefined mRotation=ROTATION_90} s.15778}

02-04 08:00:41.348 1137 4111 I ActivityTaskManager: Override config changes=20000480 {1.0 0 206mcc30mnc [en_GB,en_US,nl_BE] ldltr sw454dp w951dp h421dp 380dpi nrml long hdr widecg land night force dark=0 finger -keyb/v/h -nav/h winConfig={ mBounds=Rect(0, 0 - 2340, 1080) mAppBounds=Rect(80, 0 - 2340, 1080) mWindowingMode=fullscreen mDisplayWindowingMode=fullscreen mActivityType=undefined mAlwaysOnTop=undefined mRotation=ROTATION_90} s.15778} for displayId=0

02-04 08:00:41.357 18029 18029 E SensorManager: unregisterListenerImpl callingApp: com.google.android.youtube,callingPid:18029,callingUid:10068

02-04 08:00:41.357 845 895 I sensors-hal: batch:183, android.sensor.accelerometer/4, period=2404000, max_latency=0

02-04 08:00:41.357 845 895 I sensors-hal: batch:192, android.sensor.accelerometer/4, period=2404000, max_latency=0 request completed

02-04 08:00:41.358 845 895 I sensors-hal: batch:183, android.sensor.gyroscope_uncalibrated/18, period=2404000, max_latency=0

02-04 08:00:41.358 845 895 I sensors-hal: batch:192, android.sensor.gyroscope_uncalibrated/18, period=2404000, max_latency=0 request completed

02-04 08:00:41.358 845 895 I sensors-hal: activate:150, android.sensor.gravity/21 en=0

02-04 08:00:41.360 845 895 I sensors-hal: activate:161, android.sensor.gravity/21 en=0 completed

02-04 08:00:41.362 4843 5091 I BtGatt.ScanManager: msg.what = 8

02-04 08:00:41.365 4843 5091 I BtGatt.ScanManager: msg.what = 5

02-04 08:00:41.374 2328 3055 I Surface : opservice is null false

02-04 08:00:41.376 934 1014 I SurfaceFlinger: surface flinger receiver command 20001 .....

02-04 08:00:41.378 2328 2879 I ScreenDecorations: onDisplayChanged, displayId:0, now Rotation:0, newRotation:1

02-04 08:00:41.405 1137 2831 I chatty : uid=1000(system) OPBF_GeneralThr identical 11 lines

02-04 08:00:41.414 2328 2328 E ndroid.systemu: Invalid ID 0x00000000.

02-04 08:00:41.415 2328 2328 E ndroid.systemu: Invalid ID 0x00000000.

02-04 08:00:41.419 2328 2879 I ScreenDecorations: onPreDraw pass, mRotation:1, mOpPendingRotationChange:false, mOpPendingRotationChangeBottom:false, mLastLockTime:1580798435761

02-04 08:00:41.423 1137 1251 I InputManager-JNI: Viewport [0] to add: local:19260235133379457

02-04 08:00:41.425 1137 1958 I InputReader: Reconfiguring input devices. changes=0x00000004

02-04 08:00:41.425 1137 1958 I InputReader: Device reconfigured: id=6, name='synaptics,s3320', size 1080x2340, orientation 1, mode 1, display id 0

02-04 08:00:41.433 934 934 E Layer : [ScreenDecorOverlay#0] No local sync point found

02-04 08:00:41.455 2328 2879 I ScreenDecorations: onPreDraw pass, mRotation:1, mOpPendingRotationChange:false, mOpPendingRotationChangeBottom:false, mLastLockTime:1580798435761

02-04 08:00:41.464 8047 21533 W System.err: com.google.gson.JsonSyntaxException: java.lang.IllegalStateException: Expected BEGIN_OBJECT but was STRING at path $

02-04 08:00:41.464 8047 21533 W System.err:	at com.google.gson.internal.bind.ReflectiveTypeAdapterFactory$a.read(ReflectiveTypeAdapterFactory.java:16)

02-04 08:00:41.464 8047 21533 W System.err:	at a.m.d.j.a(Gson.java:92)

02-04 08:00:41.464 8047 21533 W System.err:	at a.m.d.j.a(Gson.java:100)

02-04 08:00:41.464 8047 21533 W System.err:	at kin.base.responses.TransactionDeserializer.deserialize(TransactionDeserializer.java:6)

02-04 08:00:41.464 8047 21533 W System.err:	at kin.base.responses.TransactionDeserializer.deserialize(TransactionDeserializer.java:1)

02-04 08:00:41.465 8047 21533 W System.err:	at com.google.gson.internal.bind.TreeTypeAdapter.read(TreeTypeAdapter.java:13)

02-04 08:00:41.465 8047 21533 W System.err:	at a.m.d.j.a(Gson.java:92)

02-04 08:00:41.465 8047 21533 W System.err:	at a.m.d.j.a(Gson.java:63)

02-04 08:00:41.465 8047 21533 W System.err:	at a.m.d.j.a(Gson.java:86)

02-04 08:00:41.466 8047 21533 W System.err:	at kin.base.requests.StreamHandler$1.onMessage(StreamHandler.java:2)

02-04 08:00:41.466 8047 21533 W System.err:	at a.n.a.b$b.a(RealServerSentEvent.java:23)

02-04 08:00:41.466 8047 21533 W System.err:	at a.n.a.b$b.a(RealServerSentEvent.java:2)

02-04 08:00:41.466 8047 21533 W System.err:	at a.n.a.b.a(RealServerSentEvent.java:12)

02-04 08:00:41.466 8047 21533 W System.err:	at a.n.a.b$a.onResponse(RealServerSentEvent.java:3)

02-04 08:00:41.466 8047 21533 W System.err:	at okhttp3.RealCall$AsyncCall.execute(RealCall.java:4)

02-04 08:00:41.466 8047 21533 W System.err:	at okhttp3.internal.NamedRunnable.run(NamedRunnable.java:3)

02-04 08:00:41.466 8047 21533 W System.err:	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1167)

02-04 08:00:41.467 8047 21533 W System.err:	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:641)

02-04 08:00:41.467 8047 21533 W System.err:	at java.lang.Thread.run(Thread.java:919)

02-04 08:00:41.467 8047 21533 W System.err: Caused by: java.lang.IllegalStateException: Expected BEGIN_OBJECT but was STRING at path $

02-04 08:00:41.467 8047 21533 W System.err:	at a.m.d.y.x.a.a(JsonTreeReader.java:4)

02-04 08:00:41.467 8047 21533 W System.err:	at a.m.d.y.x.a.beginObject(JsonTreeReader.java:1)

02-04 08:00:41.467 8047 21533 W System.err:	at com.google.gson.internal.bind.ReflectiveTypeAdapterFactory$a.read(ReflectiveTypeAdapterFactory.java:4)

02-04 08:00:41.467 8047 21533 W System.err:	... 18 more

02-04 08:00:41.472 2328 2879 I ScreenDecorations: onPreDraw pass, mRotation:1, mOpPendingRotationChange:false, mOpPendingRotationChangeBottom:false, mLastLockTime:1580798435761

02-04 08:00:41.479 2328 2879 I ScreenDecorations: receive onConfigurationChanged, newConfig.orientation:2, getRotation:1

02-04 08:00:41.482 2328 2328 E ndroid.systemu: Invalid ID 0x00000000.

02-04 08:00:41.482 2328 2328 E ndroid.systemu: Invalid ID 0x00000000.

02-04 08:00:41.485 2328 2328 E ndroid.systemu: Invalid ID 0x00000000.

02-04 08:00:41.486 31151 31151 I AndroidWidgetMessagesListProvider: [unknown:0] Invoking onReceive() with action = com.readdle.spark.action.UPDATE_ALL_MESSAGES_LIST_WIDGETS

02-04 08:00:41.487 31151 31151 I AndroidWidgetMessagesListProvider: [unknown:0] Invoking updateWidgetsFromSparkAppSystem(), widgets count = 0, this reference = com.readdle.spark.ui.widget.messageslist.AndroidWidgetMessagesListProvider@41ebe47

02-04 08:00:41.492 2328 2879 I ScreenDecorations: onPreDraw pass, mRotation:1, mOpPendingRotationChange:false, mOpPendingRotationChangeBottom:false, mLastLockTime:1580798435761

02-04 08:00:41.493 31151 31151 I AndroidWidgetInboxSummaryProvider: [unknown:0] Invoking onReceive() with action = com.readdle.spark.action.UPDATE_ALL_INBOX_SUMMARY_WIDGETS

02-04 08:00:41.494 31151 31151 I AndroidWidgetInboxSummaryProvider: [unknown:0] Invoking updateWidgetsFromSparkAppSystem(), widgets count = 0, this reference = com.readdle.spark.ui.widget.inboxsummary.AndroidWidgetInboxSummaryProvider@fad674

02-04 08:00:41.494 2328 2464 E ndroid.systemu: Invalid ID 0x00000000.

02-04 08:00:41.495 2328 2879 I ScreenDecorations: onPreDraw pass, mRotation:1, mOpPendingRotationChange:false, mOpPendingRotationChangeBottom:false, mLastLockTime:1580798435761

02-04 08:00:41.499 2328 2464 E ndroid.systemu: Invalid ID 0x00000000.

02-04 08:00:41.500 2328 2464 E ndroid.systemu: Invalid ID 0x00000000.

02-04 08:00:41.504 2328 2464 E ndroid.systemu: Invalid ID 0x00000000.

02-04 08:00:41.504 2328 2464 I chatty : uid=10046(com.android.systemui) SysUiBg identical 1 line

02-04 08:00:41.504 2328 2464 E ndroid.systemu: Invalid ID 0x00000000.

02-04 08:00:41.517 2328 2328 E ndroid.systemu: Invalid ID 0x00000000.

02-04 08:00:41.539 18029 18357 E CardboardViewNativeImpl: Surface size 2260x1080 does not match the expected screen size 2340x1080. Stereo rendering might feel off.

02-04 08:00:41.580 18029 21980 I OnePlusAudioTrackInjector: stop() packageName: com.google.android.youtube, sampleRate: 44100

02-04 08:00:41.581 1137 2002 I AS.AudioService: playerEvent: 17655 event: 3 isMusicActive:true device:2 currentPackageName:com.google.android.youtube

02-04 08:00:41.581 1137 2002 I OpAudioMonitor: MDM,stop.

02-04 08:00:41.582 1137 2002 I OpAudioMonitor: MDM,stop startTime:1580799633 endTime:1580799641

02-04 08:00:41.582 1137 2002 I OpAudioMonitor: MDM, playing,device:5 lapse:8

02-04 08:00:41.582 1137 2002 I OpAudioMonitor: MDM,device:2 lapse:8 packageName:com.google.android.youtube

02-04 08:00:41.582 1137 2002 I OpAudioMonitor: MDM,stop remove start time for:com.google.android.youtube

02-04 08:00:41.582 1137 2035 I OpAudioMonitor: logMdm run preserveOsData tag:audio_connect

02-04 08:00:41.583 564 564 E SELinux : avc: denied { find } for interface=vendor.qti.hardware.servicetracker::IServicetracker sid=u:r:system_server:s0 pid=1137 scontext=u:r:system_server:s0 tcontext=u:object_r:default_android_hwservice:s0 tclass=hwservice_manager permissive=0

02-04 08:00:41.585 4843 5409 I AddressedMediaPlayer_ext: null queue from com.google.android.youtube, constructing single-item list

02-04 08:00:41.585 1137 2002 I AS.AudioService: playerEvent: 17655 event: 4 isMusicActive:true device:2 currentPackageName:com.google.android.youtube

02-04 08:00:41.585 1137 2002 I OpAudioMonitor: MDM,stop.

02-04 08:00:41.586 1137 2002 I AS.AudioService: releasePlayer: 17655 currentPackageName:com.google.android.youtube

02-04 08:00:41.586 564 564 E SELinux : avc: denied { find } for interface=vendor.qti.hardware.servicetracker::IServicetracker sid=u:r:system_server:s0 pid=1137 scontext=u:r:system_server:s0 tcontext=u:object_r:default_android_hwservice:s0 tclass=hwservice_manager permissive=0

02-04 08:00:41.586 4843 5409 E HeadsetStateMachine: returning mCurrentState as Disconnected

02-04 08:00:41.587 1256 12068 I OMX_VPP : send_command In 0 param1 2

02-04 08:00:41.587 4843 5409 E HeadsetStateMachine: returning mCurrentState as Disconnected

02-04 08:00:41.587 4843 5409 I Avrcp_ext: updatePlayStatusForDevice: device: null

02-04 08:00:41.587 4843 5409 I Avrcp_ext: Exit updatePlayStatusForDevice

02-04 08:00:41.587 4843 5409 E HeadsetStateMachine: returning mCurrentState as Disconnected

02-04 08:00:41.587 4843 5409 E HeadsetStateMachine: returning mCurrentState as Disconnected

02-04 08:00:41.587 4843 5409 I Avrcp_ext: updatePlayStatusForDevice: device: null

02-04 08:00:41.588 4843 5409 I Avrcp_ext: Exit updatePlayStatusForDevice

02-04 08:00:41.588 4843 5409 E HeadsetStateMachine: returning mCurrentState as Disconnected

02-04 08:00:41.588 4843 5409 E HeadsetStateMachine: returning mCurrentState as Disconnected

02-04 08:00:41.588 4843 5409 I Avrcp_ext: updatePlayStatusForDevice: device: null

02-04 08:00:41.588 4843 5409 I Avrcp_ext: Exit updatePlayStatusForDevice

I'm guessing this one is the culprit:

02-04 08:00:41.539 18029 18357 E CardboardViewNativeImpl: Surface size 2260x1080 does not match the expected screen size 2340x1080. Stereo rendering might feel off.

(my screen size is 2340 x 1080)

So some sort of resolution issue, if I'm on the right track. I tried disabling/enabling 'Resolution Checks' but that doesn't help.

When searching the thread (also very important!) I just found this:

But that's a reply to someone who just wants to replace the APK and considering the date (Oct '18) it may not be valid anymore.

TL;DR

Logs! Search! ;)