Realtime WYSIWYG editor "The WebSocket URL is missing"

Hi there,

installed the plugin again after updating to 14.3.1 but had no luck, console throws error

“The WebSocket URL is missing. Aborting attempt to configure a realtime session. loader.js:35
loader.js:44 Uncaught TypeError: k.bootstrap is not a function
at loader.js:44:10
at Object.execCb (require.min.js?r=1:5:16727)
at e.check (require.min.js?r=1:5:10499)
at e. (require.min.js?r=1:5:12915)
at require.min.js?r=1:5:1542
at require.min.js?r=1:5:13376
at each (require.min.js?r=1:5:1020)
at emit (require.min.js?r=1:5:13344)
at e.check (require.min.js?r=1:5:11058)
at e. (require.min.js?r=1:5:12915)”
loader.js path …xwiki/webjars/wiki%3Axwiki/xwiki-platform-realtime-webjar/14.3.1/loader.js

Can’t find any info where to set websocket url… May other error? Thanks for help!