1. Open the page
2. Click "Edit"
3. Make edits
4. Click "Refresh"

TO BE:
The editor should close and open the edited page.
AS IS:
An error occurs.
"Connection timed out. If this happens again, contact your Confluence administrator. You may be using a proxy server that blocks WebSocket connections."
Office proxy is indeed used and there is no possibility to change it.
Are there any other ways out? What does WebSocket use?