Example iris-chat.html:16 Uncaught (in promise) TypeError: Cannot read property 'addChatButton' of undefined

[i001962]

Do you want to request a feature or report a bug?
Bug
In the example folder there is iris-chat.html. When it is loaded it throws an error.

line:16 Uncaught (in promise) TypeError: Cannot read property 'addChatButton' of undefined

What is the current behavior?:
no chat demo is rendered
What is the expected behavior?:
chat demo
Please provide the steps to reproduce or a link (repository) to a Short, Self Contained, Correct (Compilable), Example (SSCE):
Here is a deployed page with my public key for iris
https://plato.seallake.net/API/v1/data/demodata/iris-chat.html

Please mention other relevant information:
I did change the gun peer to gun-us.herokuapp.com/gun