My users are receiving an error as above. I did generate an API access key with a view to sharing data between my local install and the table on Forge. I beleive they had this issue beforehand in any case.
The game is set to Public as I have not yet asked to create a forge account as we are still in the early stages.
The error seems to indicate the API key has perhaps expired.
If you’re certain your players need to browse through your Asset Library then you can create a new API key for them that will not expire.
For normal play, the players don’t need the API key and they will access their own Assets Library (which for players is 100mb, enough for a lot of avatar and token images).
For a guide on the API key manager, please read this: The Forge API Key Manager
If you find that your players don’t actually need an API key, as soon as they remove the existing key, which has probably expired, the error will go away.
Hope this helps!