android conference sample cannot subscribe ，is crash

[afei00615]

this is the log：
2021-01-05 17:40:19.424 3360-4213/owt.sample.conference D/OWT: create offer
2021-01-05 17:40:19.447 3360-3514/owt.sample.conference E/OWT_CONF: Failed to subscribe SessionDescription is NULL.
2021-01-05 17:40:19.474 3360-3504/owt.sample.conference D/OWT: Wrong condition.
2021-01-05 17:40:19.474 3360-3504/owt.sample.conference D/OWT: dalvik.system.VMStack.getThreadStackTrace(Native Method)
2021-01-05 17:40:19.475 3360-3504/owt.sample.conference D/OWT: java.lang.Thread.getStackTrace(Thread.java:1558)
2021-01-05 17:40:19.475 3360-3504/owt.sample.conference D/OWT: owt.base.CheckCondition.printStackTrace(CheckCondition.java:59)
2021-01-05 17:40:19.475 3360-3504/owt.sample.conference D/OWT: owt.base.CheckCondition.RCHECK(CheckCondition.java:41)
2021-01-05 17:40:19.475 3360-3504/owt.sample.conference D/OWT: owt.base.CheckCondition.DCHECK(CheckCondition.java:33)
2021-01-05 17:40:19.475 3360-3504/owt.sample.conference D/OWT: owt.conference.ConferenceClient.getPeerConnection(ConferenceClient.java:505)
2021-01-05 17:40:19.475 3360-3504/owt.sample.conference D/OWT: owt.conference.ConferenceClient.onProgressMessage(ConferenceClient.java:639)
2021-01-05 17:40:19.475 3360-3504/owt.sample.conference D/OWT: owt.conference.SignalingChannel.lambda$null$7$SignalingChannel(SignalingChannel.java:113)
2021-01-05 17:40:19.475 3360-3504/owt.sample.conference D/OWT: owt.conference.-$$Lambda$SignalingChannel$vEze82r4HvjvcbCPecLEzAzAn_s.run(Unknown Source:4)
2021-01-05 17:40:19.475 3360-3504/owt.sample.conference D/OWT: java.util.concurrent.ThreadPoolExecutor.processTask(ThreadPoolExecutor.java:1187)
2021-01-05 17:40:19.475 3360-3504/owt.sample.conference D/OWT: java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1152)
2021-01-05 17:40:19.475 3360-3504/owt.sample.conference D/OWT: java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:641)
2021-01-05 17:40:19.475 3360-3504/owt.sample.conference D/OWT: java.lang.Thread.run(Thread.java:784)
2021-01-05 17:40:19.476 3360-3504/owt.sample.conference W/mple.conferenc: Accessing hidden method Lcom/msic/qarth/PatchStore;->createDisableExceptionQarthFile(Ljava/lang/Throwable;)Z (blacklist, JNI)
2021-01-05 17:40:19.477 3360-3504/owt.sample.conference E/mple.conferenc: [qarth_debug:] get PatchStore::createDisableExceptionQarthFile method fail.
2021-01-05 17:40:19.479 3360-3504/owt.sample.conference E/AndroidRuntime: FATAL EXCEPTION: pool-3-thread-1
Process: owt.sample.conference, PID: 3360
java.lang.RuntimeException: Wrong condition.
at owt.base.CheckCondition.RCHECK(CheckCondition.java:42)
at owt.base.CheckCondition.DCHECK(CheckCondition.java:33)
at owt.conference.ConferenceClient.getPeerConnection(ConferenceClient.java:505)
at owt.conference.ConferenceClient.onProgressMessage(ConferenceClient.java:639)
at owt.conference.SignalingChannel.lambda$null$7$SignalingChannel(SignalingChannel.java:113)
at owt.conference.-$$Lambda$SignalingChannel$vEze82r4HvjvcbCPecLEzAzAn_s.run(Unknown Source:4)
at java.util.concurrent.ThreadPoolExecutor.processTask(ThreadPoolExecutor.java:1187)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1152)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:641)
at java.lang.Thread.run(Thread.java:784)