websocket websocket webinar webinar websocket api elektron websockets api elektron api edp python websocket api market data sample request authentication ert in cloud api ewa websockets connection python api cloud trep posting connectivity login error refresh batch snapshot license websocket java Service marketbyorder state historical conflation ADS realtime trep elektron c# ert aws webscoket json disconnect documentation node.js streaming market status batchrequest trep api symbology view ric multiple record creation and updating. keys port authentication token tsa token delayed mitch simplified stream websock chain ric composite exchange codes ask erp websocket android fx phyton sso approval .net 502 streamstate error code 400 analytics dds_trce market data fields OMM unable identifiers post performance deniedbysrc dds marketprice error message wss exception c# .net web api ric api call date elektron connect fx rate ws api-key rmtes reuters api override client test access news analytics historical data address caching symbol subscriptions MarketFeed failure domain redundancy connection closed authhostname posting websockets timeout eikon sink_driven_src webscoket api testing csharp bid #python economic indicators status ric time and sales composite eap web sockets json bad gateway error 400 trkd websockets java streaming websockets post access samples qos condition codes suspect ews news trkd streaming descriptions api requests contribution access denied partial trkd level 2 login elektron_dd failover key tick synchronous rfa java production url ezd c# .net api real-time-data credentials limitation