This error several days. I stumbled upon it on September 22, 2017
Changing the browser does not help, then there are no cookies.
It helps to change the version of the OF lower.
I tried 4.1.1, 4.1.3, 4.1.4 - on these versions webchat is a works.
When moving to 4.1.5 - webchat breaks down.
and starting work web-page http://xxx.xx:7070/ with one folder "ofmeet-cdn"
Inside the folder - I have text: Move on, nothing here…
I found this file in folder /usr/share/openfire/resources/spank/ofmeet-cdn
Perhaps the connection between these events does not exist …