The Firefox Add-ons are not developed enough as a platform for us to continue supporting it.
Please stop using the Jaxx Firefox Add-on immediately and pair your wallet to another platform with your 12 word Backup Phrase available in MENU > Tools > Backup Wallet . View backup Phrase.
You can see which platforms Jaxx is available for download at Jaxx.io.
We are no longer supporting the Jaxx Firefox Add-on effective immediately; if you are still using it, it will be our most outdated version and you will be doing it at your own discretion.