It seems there are still load balancing issues with the new AOM site which is why it here one moment and gone the next. As of this posting, the new AOM site is up and running. They have also pulled a mass amount of add-ons out of the Sandbox.
The Sandbox is where add-ons start their life and where they will remain until they have been tested and found worthy to be placed on the public side. For a more detailed explanation of the Sandbox see Claus Valca comment on the post AOM (was) Launched
So, if you follow a link to an add-on get the message “Add-on not found!” and are redirected to the main add-ons site, chances are it is the sandbox. So, you ask how does one access the Sandbox? Well it is a bit of a tedious process:
- First, you have to be registered with Mozilla Add-ons.
- Once you have registered, you need to log-in.
- Once you are logged in, click on your e-mail address displayed on the upper right portion of the screen.
- This will open the profile screen. Check the option ‘Show sandbox?’
- When you return to the add-ons site you will still be in the public section as designated by the grey bar. Click the link for Sandbox.
- Once you click the ‘Sandbox’ link the header should look like the one below and you will able to search for add-ons within the Sandbox. To return to the ‘Public’ area just click the public link.
In the future the Mozilla developers may allow access to add-ons in the sandbox via a direct link, but will give users a warning. In the meantime users are simply going to get the “Add-on not found!” message and be redirected the main Add-ons page. On a positive note, if the add-on is in the ‘Public’ area, the old links/URLs will still work.