Cannot broadcast WebRTC on Red5Pro 5.2.0 - webrtc

Question

We're trying to use a default broadcast via WebRTC webpage that comes with Red5Pro server
https://hostname-here/live/broadcast.jsp?host=hostname-here
Client logs:
[live]:: Publish options:
{
"protocol": "wss",
"port": 8083,
"app": "live",
"streamMode": "live",
"mediaElementId": "red5pro-publisher",
"iceServers": [
{
"urls": "stun:stun2.l.google.com:19302"
}
],
"iceTransport": "udp",
"bandwidth": {
"audio": 56,
"video": 750
},
"mediaConstraints": {
"audio": true,
"video": {
"width": {
"min": 640,
"max": 640
},
"height": {
"min": 480,
"max": 480
},
"frameRate": {
"min": 8,
"max": 24
}
}
},
"host": "hostname-here",
"streamName": "teststream2"
}
red5pro-sdk.min.js:formatted:5033 2019-04-14T18:16:58.931Z - [red5pro-sdk] debug: (RTCPublisher) [publish]
red5pro-sdk.min.js:formatted:5033 2019-04-14T18:16:58.931Z - [red5pro-sdk] debug: (R5ProPublisherSocket) [websocket:setup] wss://hostname-here:8083/live?id=teststream2.
red5pro-sdk.min.js:formatted:5033 2019-04-14T18:16:58.932Z - [red5pro-sdk] debug: (R5ProPublisherSocket) [teardown] >>
red5pro-sdk.min.js:formatted:5033 2019-04-14T18:16:58.932Z - [red5pro-sdk] debug: (R5ProPublisherSocket) [WebSocket(wss://hostname-here:8083/live?id=teststream2)] close() >>
red5pro-sdk.min.js:formatted:5033 2019-04-14T18:16:58.933Z - [red5pro-sdk] debug: (R5ProPublisherSocket) << [WebSocket(wss://hostname-here:8083/live?id=teststream2)] close()
red5pro-sdk.min.js:formatted:5033 2019-04-14T18:16:58.933Z - [red5pro-sdk] debug: (R5ProPublisherSocket) << [teardown]
red5pro-sdk.min.js:formatted:255 WebSocket connection to 'wss://hostname-here:8083/live?id=teststream2' failed: Error during WebSocket handshake: Unexpected response code: 400
createWebSocket # red5pro-sdk.min.js:formatted:255
t.create # red5pro-sdk.min.js:formatted:1830
value # red5pro-sdk.min.js:formatted:2196
value # red5pro-sdk.min.js:formatted:5680
(anonymous) # r5pro-publisher-failover.js:393
promisify # r5pro-publisher-failover.js:338
publish # r5pro-publisher-failover.js:377
(anonymous) # r5pro-publisher-failover.js:198
red5pro-sdk.min.js:formatted:5033 2019-04-14T18:17:01.727Z - [red5pro-sdk] warn: (R5ProPublisherSocket) [websocketerror]: Error from WebSocket. error.
red5pro-sdk.min.js:formatted:5033 2019-04-14T18:17:01.728Z - [red5pro-sdk] debug: ([window:orientation]) [removeOrientationChangeHandler]:: onorientationchange removed.
3r5pro-publisher-failover.js:311 [Red5ProPublisher] Connect.Failure.
r5pro-publisher-failover.js:405 [live]:: Error in publish request: [object Event]
(anonymous) # r5pro-publisher-failover.js:405
Promise.catch (async)
(anonymous) # r5pro-publisher-failover.js:403
promisify # r5pro-publisher-failover.js:338
publish # r5pro-publisher-failover.js:377
(anonymous) # r5pro-publisher-failover.js:198
red5pro-sdk.min.js:formatted:5033 2019-04-14T18:17:01.731Z - [red5pro-sdk] warn: (R5ProPublisherSocket) [websocketclose]: 1006
red5pro-sdk.min.js:formatted:5033 2019-04-14T18:17:01.732Z - [red5pro-sdk] debug: (RTCPublisher) RTCPublisher
red5pro-sdk.min.js:formatted:5033 2019-04-14T18:17:01.732Z - [red5pro-sdk] debug: (R5ProPublishPeer) [teardown]
Server logs:
[WARN] [NioProcessor-20] org.red5.net.websocket.WebSocketConnection - Closing connection with status: 1002
[WARN] [NioProcessor-20] org.red5.net.websocket.codec.WebSocketDecoder - Handshake failed
org.red5.net.websocket.WebSocketException: Handshake failed, path not enabled
at org.red5.net.websocket.codec.WebSocketDecoder.parseClientRequest(WebSocketDecoder.java:302)
at org.red5.net.websocket.codec.WebSocketDecoder.doHandShake(WebSocketDecoder.java:186)
at org.red5.net.websocket.codec.WebSocketDecoder.doDecode(WebSocketDecoder.java:98)
at org.apache.mina.filter.codec.CumulativeProtocolDecoder.decode(CumulativeProtocolDecoder.java:180)
at org.apache.mina.filter.codec.ProtocolCodecFilter.messageReceived(ProtocolCodecFilter.java:253)
at org.apache.mina.core.filterchain.DefaultIoFilterChain.callNextMessageReceived(DefaultIoFilterChain.java:641)
at org.apache.mina.core.filterchain.DefaultIoFilterChain.access$1300(DefaultIoFilterChain.java:48)
at org.apache.mina.core.filterchain.DefaultIoFilterChain$EntryImpl$1.messageReceived(DefaultIoFilterChain.java:1114)
at org.apache.mina.filter.ssl.SslHandler.flushScheduledEvents(SslHandler.java:323)
at org.apache.mina.filter.ssl.SslFilter.messageReceived(SslFilter.java:565)
at org.apache.mina.core.filterchain.DefaultIoFilterChain.callNextMessageReceived(DefaultIoFilterChain.java:641)
at org.apache.mina.core.filterchain.DefaultIoFilterChain.access$1300(DefaultIoFilterChain.java:48)
at org.apache.mina.core.filterchain.DefaultIoFilterChain$EntryImpl$1.messageReceived(DefaultIoFilterChain.java:1114)
at org.apache.mina.core.filterchain.IoFilterAdapter.messageReceived(IoFilterAdapter.java:121)
at org.apache.mina.core.filterchain.DefaultIoFilterChain.callNextMessageReceived(DefaultIoFilterChain.java:641)
at org.apache.mina.core.filterchain.DefaultIoFilterChain.fireMessageReceived(DefaultIoFilterChain.java:634)
at org.apache.mina.core.polling.AbstractPollingIoProcessor.read(AbstractPollingIoProcessor.java:539)
at org.apache.mina.core.polling.AbstractPollingIoProcessor.access$1200(AbstractPollingIoProcessor.java:68)
at org.apache.mina.core.polling.AbstractPollingIoProcessor$Processor.process(AbstractPollingIoProcessor.java:1242)
at org.apache.mina.core.polling.AbstractPollingIoProcessor$Processor.process(AbstractPollingIoProcessor.java:1231)
at org.apache.mina.core.polling.AbstractPollingIoProcessor$Processor.run(AbstractPollingIoProcessor.java:683)
at org.apache.mina.util.NamePreservingRunnable.run(NamePreservingRunnable.java:64)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
at java.lang.Thread.run(Thread.java:748)
Red5Pro server has a valid SSL certificate and a public IP. The version is 5.2.0, ports 8081 and 8083 are open.
We have the libraries mentioned in this answer installed

Answer 1

Turned out the reason for the issue was the WebRTC plugin was disabled.
Not sure why I did not figure that out right away. Maybe I was confused by messages in the log about WebSocket plugin and the WebSocket error
[INFO] [main] com.red5pro.license.LicenseManager - addListener: Red5Pro-Clustering
[INFO] [main] org.red5.server.plugin.PluginLauncher - Loaded plugin: com.red5pro.cluster.plugin.ClusterPlugin
[INFO] [main] com.red5pro.license.LicenseManager - addListener: Red5Pro-RTSP-Plugin
[INFO] [main] org.red5.server.plugin.PluginLauncher - Loaded plugin: com.red5pro.rtsp.plugin.RTSPPlugin
[INFO] [main] com.red5pro.activation.ProPluginator - Version - server: RED5/1,0,10,0 pro: 5.2.0.b271-release
[INFO] [main] com.red5pro.activation.ProPluginator - Operating system: Linux version: 4.15.0-1023-azure
[INFO] [main] com.red5pro.activation.ProPluginator - Processor arch: amd64 available: 2
[INFO] [main] com.red5pro.activation.ProPluginator - Memory - free: 190632384 total: 251002880 max: 1626734592
[INFO] [main] com.red5pro.activation.ProPluginator - Starting Red5 Professional, pluginator version 5.2.0.271-RELEASE - b22d2d1 (on: 10.12.2018 09:38)
[INFO] [main] com.red5pro.override.internal.ProvisionResolverService - setting MBR spliterator ~
[INFO] [main] com.red5pro.override.internal.ProvisionResolverService - inspecting prewire
[INFO] [main] com.red5pro.license.LicenseManager - addListener: Red5Pro-SecondScreen-Websockets
[INFO] [main] com.red5pro.activation.ProPluginator - Red5 Professional Activating
[INFO] [main] com.red5pro.activation.ProPluginator - Plugination activation waiting for server to settle...
[INFO] [main] org.red5.server.plugin.PluginLauncher - Loaded plugin: com.red5pro.activation.ProPluginator
[INFO] [main] com.red5pro.license.LicenseManager - addListener: Red5Pro-Cloudstorage
[INFO] [main] org.red5.server.plugin.PluginLauncher - Loaded plugin: com.red5pro.media.storage.CloudstoragePlugin
[INFO] [main] org.red5.server.plugin.PluginLauncher - Loaded plugin: org.red5.net.websocket.WebSocketPlugin
[INFO] [main] com.red5pro.license.LicenseManager - addListener: Red5Pro-AutoScale
[INFO] [main] org.red5.server.plugin.PluginLauncher - Loaded plugin: com.red5pro.clustering.autoscale.AutoScale
[INFO] [main] org.red5.net.websocket.WebSocketTransport - WebSocket (wss) will be bound to [0.0.0.0:8083]
Maybe that helps somebody.