Mozilla is currently experiencing an issue in Firefox (Bug 15489730) which is causing all extensions, including 1Password, to be disabled. This means no extensions will work in Firefox until Mozilla resolves this issue.
In the meantime, you can still use the 1Password extension in several other browsers. If you're using 1Password with an account, you can use 1Password X (our newest browser extension) in any Chromium based browser, like Chrome, Opera, Vivaldi and Brave: Get started with 1Password X
Alternatively, you can use the legacy 1Password extension in other browsers as well. Here's the link to download the 1Password extension for Chrome and Opera: Get the 1Password extension here
We will keep this thread updated with any pertinent information that may arise.