I went to mycloud.com and tried signing in with my email/password. Wasn’t working. Tried using my email address with the “forgot password” button, and now mycloud is telling me that there’s no account associated with that email address. (I’m 100% sure that’s my email account with mycloud. Have triple checked.)
Have you checked the My Cloud Dashboard to ensure the user you are trying to sign in on MyCloud.com has cloud access enabled and has the same email address you are attempting to use on MyCloud.com?
One can always resend the cloud access email via the My Cloud Dashboard to a new email address.