expand error message when metadata was not available during fetch

[rafaelcr]

when a metadata server fails to respond with correct data (commonly IPFS nodes close to our cloud servers not having the JSON yet), we currently show this error

{
    "error": "Token error"
    "message": "Metadata could not be processed because the server responded with an error"
}

we should expand this message to add recommendations for users to be able to fix their data