UAG java.io.IOException: Connection reset by peer

[PHemme94]

Hi,

I am using Horizon 8 2103 and application streaming via RDSH. I am using a UAG to connect from external networks. 
The entire setup is working with different Horizon 7 version since years. After the update to Horizon 8 the first launch of an application closes after 1second. The user account is logged on to the RDSH and has the application started, just the html site was closed. I checked log files of RDSH,CS and UAG.

I found with the exact correct timestamp the following connection reset within the UAG log file:

05/12 07:10:07,926[nioEventLoopGroup-7-4]DEBUG proxy.HttpsProxyInterceptorHandler[log: 62][d62c1fa7-412f-4f96-9950-eed8f563d090]: ResponseWrite: 304 Not Modified on Channel : [id: 0xfbecf575, L:/10.16.210.183:31836 - R:eu0006cs01.eu0006.rosen-group.eu/10.16.210.182:443]
05/12 07:10:07,926[nioEventLoopGroup-7-4]DEBUG proxy.HttpsProxyInterceptorHandler[operationComplete: 271][d62c1fa7-412f-4f96-9950-eed8f563d090]: ResponseWrite: Successfully wrote response to client, closing=false
05/12 07:10:07,926[nioEventLoopGroup-7-4]DEBUG proxy.HttpsProxyReadHandler[log: 74][d62c1fa7-412f-4f96-9950-eed8f563d090]: Got chuncked response for event type: ProxyRead on Channel: [id: 0xfbecf575, L:/10.16.210.183:31836 - R:eu0006cs01.eu0006.rosen-group.eu/10.16.210.182:443]
05/12 07:10:07,926[nioEventLoopGroup-7-4]DEBUG proxy.HttpsProxyInterceptorHandler[channelRead: 162][d62c1fa7-412f-4f96-9950-eed8f563d090]: Processing default http response: EmptyLastHttpContent
05/12 07:10:07,926[nioEventLoopGroup-7-4]DEBUG proxy.HttpsProxyInterceptorHandler[log: 74][d62c1fa7-412f-4f96-9950-eed8f563d090]: Got chuncked response for event type: ResponseWrite on Channel: [id: 0xfbecf575, L:/10.16.210.183:31836 - R:eu0006cs01.eu0006.rosen-group.eu/10.16.210.182:443]
05/12 07:10:07,926[nioEventLoopGroup-7-4]DEBUG proxy.HttpsProxyInterceptorHandler[handleRewrites: 363][d62c1fa7-412f-4f96-9950-eed8f563d090]: No rewriting location header:EmptyLastHttpContent
05/12 07:10:07,926[nioEventLoopGroup-7-4]DEBUG proxy.HttpsProxyInterceptorHandler[operationComplete: 271][d62c1fa7-412f-4f96-9950-eed8f563d090]: ResponseWrite: Successfully wrote response to client, closing=false
05/12 07:10:10,609[nioEventLoopGroup-7-3]WARN channel.DefaultChannelPipeline[onUnhandledInboundException: 1188][d62c1fa7-412f-4f96-9950-eed8f563d090]: An exceptionCaught() event was fired, and it reached at the tail of the pipeline. It usually means the last handler in the pipeline did not handle the exception.
java.io.IOException: Connection reset by peer
at sun.nio.ch.FileDispatcherImpl.read0(Native Method)
at sun.nio.ch.SocketDispatcher.read(SocketDispatcher.java:39)
at sun.nio.ch.IOUtil.readIntoNativeBuffer(IOUtil.java:223)
at sun.nio.ch.IOUtil.read(IOUtil.java:192)
at sun.nio.ch.SocketChannelImpl.read(SocketChannelImpl.java:380)
at io.netty.buffer.PooledUnsafeDirectByteBuf.setBytes(PooledUnsafeDirectByteBuf.java:288)
at io.netty.buffer.AbstractByteBuf.writeBytes(AbstractByteBuf.java:1132)
at io.netty.channel.socket.nio.NioSocketChannel.doReadBytes(NioSocketChannel.java:347)
at io.netty.channel.nio.AbstractNioByteChannel$NioByteUnsafe.read(AbstractNioByteChannel.java:148)
at io.netty.channel.nio.NioEventLoop.processSelectedKey(NioEventLoop.java:656)
at io.netty.channel.nio.NioEventLoop.processSelectedKeysOptimized(NioEventLoop.java:591)
at io.netty.channel.nio.NioEventLoop.processSelectedKeys(NioEventLoop.java:508)
at io.netty.channel.nio.NioEventLoop.run(NioEventLoop.java:470)
at io.netty.util.concurrent.SingleThreadEventExecutor$5.run(SingleThreadEventExecutor.java:909)
at io.netty.util.concurrent.FastThreadLocalRunnable.run(FastThreadLocalRunnable.java:30)
at java.lang.Thread.run(Thread.java:748)

Any ideas`?