Hello!
It is advised to store the secret keys of your leaderboards elsewhere, as in the browser they are only held in the site's data. They might have went missing because you cleared the cache or site data. If you still own their public keys, you can DM me on Discord (@DAN#3389) and I will find their matching secret keys for you.
As for the requests that are being blocked - I have no idea. If you could be more specific and provide screenshots of the errors, I might be able to figure it out.