TypeError [ERR_INVALID_ARG_TYPE]: The "chunk" argument must be one of type string or Buffer. Received type object
    at ServerResponse.end (_http_outgoing.js:690:13)
    at /opt/backend-webrtc/pns.js:265:6
    at Layer.handle [as handle_request] (/opt/backend-webrtc-/node_modules/express/lib/router/layer.js:95:5)
    at next (/opt/backend-webrtc/node_modules/express/lib/router/route.js:137:13)
    at Route.dispatch (/opt/backend-webrtc/node_modules/express/lib/router/route.js:112:3)
    at Layer.handle [as handle_request] (/opt/backend-webrtc-/node_modules/express/lib/router/layer.js:95:5)
    at /opt/backend-webrtc/node_modules/express/lib/router/index.js:281:22
    at Function.process_params (/opt/backend-webrtc/node_modules/express/lib/router/index.js:335:12)
    at next (/opt/backend-webrtc/node_modules/express/lib/router/index.js:275:10)
    at expressInit (/opt/backend-webrtc/node_modules/express/lib/middleware/init.js:40:5)