Can't access devices through EDM since Firefox update 64.0

[Pete]

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 7.1.5.2

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

[AndyDoss]

This does not work anymore. They removed the configuration option in Firefox 69/70.

https://bugzilla.mozilla.org/show_bug.cgi?id=1504344

[jguenther]

THAT is brilliant!!!!!!!!!!
works like a charm.

[fkroeger · Accepted solution]

Since the fix (https://bugzilla.mozilla.org/show_bug.cgi?id=1398718) in Firefox 64 is only a configuration change (https://phabricator.services.mozilla.com/D6589), it can be changed back.

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.

[Quinntun]

Hey guys thanks for the info it was very much helpful. I have found a video on YouTube that allows to have two instances of Firefox installed, so the older version can be setup to just access the switches while the newer one can be used for normal day to day acticities. Fixes both issues.

How to install 2 different versions of firefox in the same computer - YouTube