I only signed in yesterday when the service got briefly restored and earlier, I received an email containing the key.
So, one thing we have noticed is that when users copy/cut and paste the activation key they receive from the emails sent out, this action actually copies one extra character (a space), leading to a lot of the activation fails that have been happening recently.
If possible, please type out your activation codes individually rather than attempting to copy and paste them in.
Hope this helps. Thanks/