We're running a lot of ERS4500 series switches ( just under 100) with Avaya v5.7.2.012 firmware. Also a small number of ERS3500 that are experiencing the same issue and our ERS8800 with Firmware 220.127.116.11
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