Karma plugin stopped working after upgrade to 2016.2

Karma server starts as usually and the "JetBrains IDE Support debugs this browser" message appears  in the browser but then

Waiting for connection from JetBrains IDE Support extension for Chrome. Please ensure you have installed the extension and IDE port configured (current port 63342), or see Help.

and 

JetBrains IDE Support extension for Chrome: Please ensure that JetBrains IDE Support extension is installed and enabled in Chrome.

and this is written to the log:

2016-07-14 15:39:03,541 [1207699] ERROR - cket.WebSocketHandshakeHandler - /root
java.nio.file.AccessDeniedException: /root
at sun.nio.fs.UnixException.translateToIOException(UnixException.java:84)
at sun.nio.fs.UnixException.rethrowAsIOException(UnixException.java:102)
at sun.nio.fs.UnixException.rethrowAsIOException(UnixException.java:107)
at sun.nio.fs.UnixFileSystemProvider.newDirectoryStream(UnixFileSystemProvider.java:427)
at java.nio.file.Files.newDirectoryStream(Files.java:589)
at com.jetbrains.javascript.debugger.sourcemap.SourceMapCollector.resolveSourcemapsInDir(SourceMapCollector.kt:57)
at com.jetbrains.javascript.debugger.sourcemap.SourceMapCollector.resolveSourcemaps(SourceMapCollector.kt:49)
at com.jetbrains.javascript.debugger.sourcemap.SourceMapCollector.collect(SourceMapCollector.kt:33)
at com.jetbrains.javascript.debugger.sourcemap.SourceMapCollectorKt.collectSourceMaps(SourceMapCollector.kt:18)
at com.jetbrains.javascript.debugger.JavaScriptDebugProcess.doInitBreakpoints(JavaScriptDebugProcess.kt:170)
at org.jetbrains.debugger.DebugProcessImpl.initBreakpoints(DebugProcessImpl.kt:239)
at org.jetbrains.debugger.DebugProcessImpl$checkCanInitBreakpoints$1.invoke(DebugProcessImpl.kt:230)
at org.jetbrains.debugger.DebugProcessImpl$checkCanInitBreakpoints$1.invoke(DebugProcessImpl.kt:47)
at org.jetbrains.debugger.connection.VmConnection.setState(VmConnection.kt:70)
at org.jetbrains.debugger.connection.VmConnection.setState$default(VmConnection.kt:62)
at com.intellij.chromeConnector.extension.ExtBackedChromeConnection.connect(ExtBackedChromeConnection.kt:75)
at com.intellij.chromeConnector.extension.ExtBackedChromeConnection$open$3$1.consume(ExtBackedChromeConnection.kt:57)
at com.intellij.chromeConnector.extension.ExtBackedChromeConnection$open$3$1.consume(ExtBackedChromeConnection.kt:25)
at org.jetbrains.concurrency.AsyncPromise$CompoundConsumer.consume(AsyncPromise.java:117)
at org.jetbrains.concurrency.AsyncPromise.setResult(AsyncPromise.java:314)
at org.jetbrains.io.jsonRpc.JsonRpcServer.messageReceived(JsonRpcServer.kt:92)
at org.jetbrains.io.webSocket.MessageChannelHandler.textFrameReceived(MessageChannelHandler.java:59)
at org.jetbrains.io.webSocket.WebSocketProtocolHandler.channelRead(WebSocketProtocolHandler.kt:22)
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:348)
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:334)
at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:326)
at io.netty.handler.codec.MessageToMessageDecoder.channelRead(MessageToMessageDecoder.java:102)
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:348)
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:334)
at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:326)
at io.netty.handler.codec.http.cors.CorsHandler.channelRead(CorsHandler.java:70)
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:348)
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:334)
at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:326)
at io.netty.channel.ChannelInboundHandlerAdapter.channelRead(ChannelInboundHandlerAdapter.java:86)
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:348)
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:334)
at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:326)
at io.netty.handler.codec.ByteToMessageDecoder.fireChannelRead(ByteToMessageDecoder.java:293)
at io.netty.handler.codec.ByteToMessageDecoder.channelRead(ByteToMessageDecoder.java:267)
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:348)
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:334)
at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:326)
at io.netty.channel.ChannelInboundHandlerAdapter.channelRead(ChannelInboundHandlerAdapter.java:86)
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:348)
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:334)
at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:326)
at io.netty.channel.DefaultChannelPipeline$HeadContext.channelRead(DefaultChannelPipeline.java:1320)
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:348)
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:334)
at io.netty.channel.DefaultChannelPipeline.fireChannelRead(DefaultChannelPipeline.java:905)
at io.netty.channel.nio.AbstractNioByteChannel$NioByteUnsafe.read(AbstractNioByteChannel.java:123)
at io.netty.channel.nio.NioEventLoop.processSelectedKey(NioEventLoop.java:563)
at io.netty.channel.nio.NioEventLoop.processSelectedKeysOptimized(NioEventLoop.java:504)
at io.netty.channel.nio.NioEventLoop.processSelectedKeys(NioEventLoop.java:418)
at io.netty.channel.nio.NioEventLoop.run(NioEventLoop.java:390)
at io.netty.util.concurrent.SingleThreadEventExecutor$5.run(SingleThreadEventExecutor.java:742)
at java.lang.Thread.run(Thread.java:745)
2016-07-14 15:39:03,541 [1207699] ERROR - cket.WebSocketHandshakeHandler - IntelliJ IDEA 2016.2 Build #IU-162.1121.32
2016-07-14 15:39:03,541 [1207699] ERROR - cket.WebSocketHandshakeHandler - JDK: 1.8.0_76-release
2016-07-14 15:39:03,541 [1207699] ERROR - cket.WebSocketHandshakeHandler - VM: OpenJDK 64-Bit Server VM
2016-07-14 15:39:03,541 [1207699] ERROR - cket.WebSocketHandshakeHandler - Vendor: JetBrains s.r.o
2016-07-14 15:39:03,541 [1207699] ERROR - cket.WebSocketHandshakeHandler - OS: Linux
2016-07-14 15:39:03,541 [1207699] ERROR - cket.WebSocketHandshakeHandler - Last Action: Rerun

bug? Or did I misconfigure something? 

Tried to change port in Idea with -Drpc.port=7777 and in extension - didn't help. Also try to increase port by one in extension.