elb ssl termination for wss websocket fails net::ERR_RESPONSE_HEADERS_TRUNCATED

I am trying to get a websocket communication working through a classic ELB with ssl termination to wowza, a java based media server.

Setup

VPC
R53
test.myTld.com 
IPv4, Alias=Yes, Target myElb, Routing Simple
CLASSIC ELB: myElb
listeners: SSL 64443 -> TCP 64443 : SSL Cert managed by AWS Certificate Manager (ACM)
security group [sg-xxxxx] : Custom TCP Rule TCP (6) 64443 0.0.0.0/0
EC2 
security group [sg-xxxxx] : Custom TCP Rule TCP (6) 64443 0.0.0.0/0

When connecting to ec2 wowza using direct ip, the connection works and stream connects

wss://xxx.xxx.xxx.xxx:64443/webrtc-session.json

Frames = {status: 200, statusDescription: “OK”, direction: “publish”, command: “sendOffer”,…}

However connecting through the ELB I get different errors being reported

WebSocket connection to 'wss://test.myTld.com:64443/webrtc-session.json' 
failed: Error during WebSocket handshake: net::ERR_RESPONSE_HEADERS_TRUNCATED

So following several tutorials & docs such as http://docs.aws.amazon.com/cli/latest/reference/elb/set-load-balancer-policies-of-listener.html I added the following

aws elb create-load-balancer-policy --load-balancer-name myElb --policy-name wowza --policy-type-name ProxyProtocolPolicyType --policy-attributes AttributeName=ProxyProtocol,AttributeValue=True
aws elb set-load-balancer-policies-for-backend-server --load-balancer-name myElb --instance-port 64443 --policy-names wowza

Confriming the policy has been updated,

aws elb describe-load-balancers --load-balancer-name myElb
"VPCId": "vpc-xxxxxxxx", 
"BackendServerDescriptions": [
 {
   "InstancePort": 64443, 
   "PolicyNames": [
                   "wowza"
                  ]
                }
            ], 
            "Instances": [
                {
                    "InstanceId": "i-xxxxxxx"
                }
            ], 

I then try a connection using the test.myTld.com & ELB, the first try reports

WebSocket connection to 'wss://test.myTld.com:64443/webrtc-session.json'
failed: Error during WebSocket handshake: Invalid status line
Frames = (Opcode -1)

then subsequent tries report

WebSocket connection to 'wss://test.myTld.com:64443/webrtc-session.json'
failed: Error during WebSocket handshake: net::ERR_RESPONSE_HEADERS_TRUNCATED
Frames = (Opcode -1)

For what it is worth, here is the logs from wowza

server  INFO    200 -   WebSocketSession.create[94728968]   -   -   -   9432.997
server  INFO    200 -   WebSocketSession.destroy[926674790]: source:server status:-1 description:Unknown    -   -   -   9490.999

So my questions is what else do I need to set for the ELB to pass the wss headers to establish the websocket.

Thx

Art

Hi Art,

It would be best if we can look at your Wowza and ELB configuration. Do please create a support ticket so that we can review this.

Michelle