Viewer of CWA for Android fail to establish connection to VDA with below given error message 
 

We were unable to connect through the proxy. Error - {0}

02-10 05:44:55.989  1117 28821 W System.err: Caused by: android.system.GaiException: android_getaddrinfo failed: EAI_NODATA (No address associated with hostname)
02-10 05:44:55.989  1117 28821 W System.err: at libcore.io.Linux.android_getaddrinfo(Native Method)
02-10 05:44:55.989  1117 28821 W System.err: at libcore.io.ForwardingOs.android_getaddrinfo(ForwardingOs.java:73)
02-10 05:44:55.989  1117 28821 W System.err: at libcore.io.BlockGuardOs.android_getaddrinfo(BlockGuardOs.java:202)
02-10 05:44:55.989  1117 28821 W System.err: at java.net.Inet6AddressImpl.lookupHostByName(Inet6AddressImpl.java:135)
02-10 05:44:55.989  1117 28821 W System.err: ... 7 more
02-10 05:44:55.990 27806 28696 E "Network": "ERROR     ( 2)","Proxy Failed, ex = We were unable to tunnel through the proxy.
02-10 05:44:55.990 27806 28696 E "Network": 
02-10 05:44:55.990 27806 28696 E "Network": We were unable to connect through the proxy. Error - {0}
02-10 05:44:55.990 27806 28696 E "Network": "
02-10 05:44:55.990 27806 28696 E "Network": "ERROR     ( 2)","skipping proxy and rethrowing exception "
02-10 05:44:55.990 27806 27806 I ViewRootImpl@94e8c4d[ReceiverViewActivityMultiprocess]: Relayout returned: old=(0,51,2560,1498) new=(576,591,1983,957) req=(1407,366)0 dur=15 res=0x6 s={true -5476376645794361344} ch=true fn=-1
02-10 05:44:55.990 27806 28696 E "Network": "ERROR     ( 2)","Received Exception  in parent catch"
02-10 05:44:55.990 27806 28696 V "Network": "DEBUG1    ( 6)","Closing base socket"
02-10 05:44:55.990 27806 28696 V "Network": "DEBUG1    ( 6)","currentProxyNo:1"
02-10 05:44:55.990 27806 28696 V "Network": "DEBUG1    ( 6)","is currentProxy CGP:false"
02-10 05:44:55.990 27806 28696 V "Network": "DEBUG1    ( 6)","is currentProxy SSL:false"
02-10 05:44:55.990 27806 28696 V "Network": "DEBUG1    ( 6)","checking next proxy availablity"
02-10 05:44:55.990 27806 28696 V "Network": "DEBUG1    ( 6)","next proxy is available"
02-10 05:44:55.990 27806 27806 D ScrollView:  onsize change changed 
02-10 05:44:55.991 27806 28696 V "Network": "DEBUG1    ( 6)","updating hst prt"
02-10 05:44:55.991 27806 28696 V "SocketFactory": "DEBUG1    ( 6)","Connecting proxy com.citrix.hdx.client.io.net.ip.proxy.b@bef92eb to randomadcaddress:443"
02-10 05:44:55.991 27806 28696 V "Network": "DEBUG1    ( 6)","Calling currentProxy.connect(), currentProxy = com.citrix.hdx.client.io.net.ip.proxy.b@bef92eb"
02-10 05:44:55.991 27806 27806 I ViewRootImpl@94e8c4d[ReceiverViewActivityMultiprocess]: [DP] dp(1) 1 android.view.ViewRootImpl.reportNextDraw:11078 android.view.ViewRootImpl.performTraversals:3915 android.view.ViewRootImpl.doTraversal:2669 
02-10 05:44:55.991 27806 27806 I ViewRootImpl@94e8c4d[ReceiverViewActivityMultiprocess]: [DP] pd() Asnyc report
02-10 05:44:55.991 27806 28696 E "Network": "ERROR     ( 2)","Proxy Failed, ex = We were unable to tunnel through the proxy.
02-10 05:44:55.991 27806 28696 E "Network": 
02-10 05:44:55.991 27806 28696 E "Network": We were unable to connect through the proxy. Error - {0}
02-10 05:44:55.991 27806 28696 E "Network": "
02-10 05:44:55.991 27806 28696 E "Network": "ERROR     ( 2)","skipping proxy and rethrowing exception "
02-10 05:44:55.992 27806 27806 I ViewRootImpl@94e8c4d[ReceiverViewActivityMultiprocess]: mAttachInfo.mThreadedRenderer.draw, mView = DecorView@6623969[ReceiverViewActivityMultiprocess] w = 1407 h = 366
02-10 05:44:55.992 27806 28696 E "Network": "ERROR     ( 2)","Received Exception  in parent catch"
02-10 05:44:55.992 27806 28696 V "Network": "DEBUG1    ( 6)","Closing base socket"
02-10 05:44:55.992 27806 28696 V "Network": "DEBUG1    ( 6)","lastIOException = com.citrix.hdx.client.io.net.ip.proxy.ProxyException: We were unable to tunnel through the proxy.
02-10 05:44:55.992 27806 28696 V "Network": 
02-10 05:44:55.992 27806 28696 V "Network": We were unable to connect through the proxy. Error - {0}
02-10 05:44:55.992 27806 28696 V "Network": "
02-10 05:44:55.993 27806 28696 E "Network": "ERROR     ( 2)","Received IOEx: We were unable to tunnel through the proxy.
02-10 05:44:55.993 27806 28696 E "Network": 
02-10 05:44:55.993 27806 28696 E "Network": We were unable to connect through the proxy. Error - {0}
02-10 05:44:55.993 27806 28696 E "Network": "
02-10 05:44:55.994 27806 28696 V "Network": "DEBUG1    ( 6)","Transport Driver.run() IO exception"
02-10 05:44:55.996  1117  4628 I InputDispatcher: Focus left window (27806): f3301da in display 0 0

• Workaround: Set google.dns as the DNS resolver on Android as per Get Started  |  Public DNS  |  Google Developers 
• Permanent Solution: Fix DNS resolution to make sure CWA for Android gets the correct ADC gateway address.  

Problem Cause