Unable to execute EMS on RPi3 b

I am trying to deploy ems on RPi3 b. My ems seems to be connected, but when I am running LSR I am getting below error,

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[INFO ] 2018-05-09 09:06:48,19 ./wsems: Creating the WsEms proxy.
[INFO ] 2018-05-09 09:06:48,19 ./wsems: Starting HTTP Server.
[ERROR] 2018-05-09 09:06:48,19 Main: Error initializing HTTP Server
[FORCE] 2018-05-09 09:06:48,19 Main: Exiting....
[DEBUG] 2018-05-09 09:06:48,19 jsonConfigurator::~jsonConfigurator: Deleting JSON object

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Below is my config.json file :

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 "ws_servers": [{
 "host": "192.168.43.25",
 "port": 8080
 }],
 "http_server": {
 "host": "127.0.0.1",
 "port": 8090,
 "ssl": false,
 "authenticate": false
 },
 "appKey": "990d0f05-c17f-4416-aa07-beefd1e61b50",
 "logger": {
 "level": "DEBUG"
 },
 "auto_bind": [{
 "name": "PiThing",
 "gateway": false
 }],
 "certificates": {
 "validate": false,
 "allow_self_signed":true
 },
 "ws_connection": {
 "encryption": "none",
 "verbose": true,
 "msg_timeout": 1000
 }
}