Websocket app partially fails in Shinyapps.io


I wrote a simple shiny app that pulls real-time data (crypto prices) via websocket connections (using websocket::). Works like a charm locally, but when deployed to Shinyapps.io (free version), two of my four endpoints fail.

Local on top, followed by shinyapps, followed by the logs from shinyapps.io:

The two websocket feeds that fail are not connecting. I wonder if there is a compatibility issue or something similar.

For reference, these are the public websocket feeds that fail:
"wss://ws.okex.com:8443/ws/v5/public/" with message:
{"op": "subscribe",
"args": [{
"channel": "tickers",
"instId": "BTC-USD-SWAP"}]}'

Thanks in advance for any pointers.