There are a lot of reasons why this error could happen, but the most common one is, that your browser is not allowing cookies for RoGold.
This is the most common reason for issues. It happens because of an old RoGold cookie interfering with a new one.
Clear all cookies which originates from rogold.live, while you are on the Roblox website.
You can find this dialog by clicking the lock (or whatever other icon they use) next to the website url:
When in this dropdown, please look for something saying cookies:
Click that, and you should find the popup dialog.
Now, click the trash icon next to anything that has "rogold.live" in it.
After this, re-enter your key, and it should work.
After entering your key, you might see this on the right of your search bar (in Chrome). Make sure to allow the site to save data, if you do see it:
You can also access it from here on most browsers:
After this, try entering your key again.
The internet is currently working on phasing out `Third-party cookies`, which is generally a good thing as it prevents tracking. However, we utilize it to make our extension work.
Go into your cookie settings in your browser
Then add `[*.]rogold.live` as a site allowed to use third-party cookies.
This might have fixed it, re-enter your key.
Check for any existing cookies from "rogold.live" on the Roblox website. If there are any, delete them. Then try enter your key again.
If none of the above methods worked, it might be because of an adblocker in your browser. For example Brave has a built-in Adblocker. Try disabling that for the Roblox website.
This should now mean that you can enter your key without issues. If you still experience issues, try joining our Discord and make a support ticket: discord.gg/rogold