Firefox yesterday broke all add-ons because they forgot to renew the certificate. This includes downloading of all add-ons.
There is now a lot of articles about it over the internet, the official tread where the issue is being tracked and solved is here:
But more info about current state is on their Twitter page:
Right now, the fix they released should be working for most users, except for ESR 60 version and Android version.
If your add-ons are still disabled, don't panic, don't reinstall anything, the best thing to do is doing nothing.
Since millions of people is affected, this kind of serious issue will be promptly fixed by Firefox team.
If you cannot just wait and enjoy Sunday and you really need your dials page now, you have several options.
The easiest way is using the cloud dials page - but this works only if you have created cloud account: https://group-speed-dial.fastaddons.com/cloud
Another easy option is temporary load your addons based from about:debugging page, see the steps from the frst post here:
After you have your dials working agin, make sure to create a backup from Options page / "Import /backup" tab.