Hi

This may not be an issue with Firefox as I can see that you need to download specific software for Windows.

If you need to install a Firefox add-on, it may be the case that Cisco (the people behind WebEx, have not updated it in line with Mozilla's new security requirements. Cisco will be able to give you further information around this, and should also be able to provide support in respect of their software.

I recommend you contact them through their support channels at this link.

I hope this helps, but if not, please come back here and we can look into a different solution for you.

This will disable add-on signature enforcement; Enter about:config into your Firefox address bar Click the I'll be careful button Find xpinstall.signatures.required in the list Right click the preference Select Toggle until the value is false https://support.mozilla.org/en-US/kb/add-on-signing-in-firefox

https://wiki.mozilla.org/Firefox/AddOns/Status/Updates#Exec_Summary “Currently targeting Signing with no pref to turn off in Firefox 47”