Xibo Android v4 HTML widget white screen

I am having troubles with displaying some HTML pages.
If I add ex. https://google.com, it is displayed, but if I want to add specific website that is hostet inside our company, it only shows me white screen. From preview it is working and it is accessible from CMS and player subnet.
I tried with hosting .pdf and .html and both shows same white screen.

Please advise.
Thank you.

Hello @urban.zaloznik

Welcome to the community Xibo Forum.

Players use the websocket of the devices they are on.

Try it first with the embeded Android Browser.

What device are you using?