Since the Firefox browser update to V64.0 we are unable to access any of the switches using EDM. After the initial login completes it shows '"Discovering Device, please wait' but never progresses.
We have found that devices with Extreme branded firmware :v5.3.8.014 are still working.
When we open the Firefox Web Developer - Debug console we see a message like the following;
TypeError: webServerName is undefined[Learn More] edmContentJs.js:1631:299
Best answer by fkroeger
Simply insert about:config in the address bar, accept the warning and search for dom.xhr.lowercase_header.enabled and double click it in order to set it to false.
With this change EDM on 5600's is accessible with the newest MFF version.