I am having this issue in IE/Edge with the latest version installed. When a customer clicks our widget we get notification in the operator panel and when we click on the customer nothing happens but the consule shows the following error SCRIPT 5009: promise.js is undefined functions.js (46,12943). I can also get the same error if I try to end a the conversation in IE by clicking on the red end conversation icon on the widget.
I thought this had something to do with fonts but I have checked IIS and it is serving WOFF and WOFF2 fonts.
Can you shine any light on this.