PrivateSky looks like it had the same failing as LavaBit in that the service provider actually had access to the decryption key for your email. So encryption in these services was vulnerable to a court order imposed on the service provider to use or share the key.
I'm not saying Tutanota don't have an issue like this but their main selling point appears to be that this isn't the case.
I'm not saying Tutanota don't have an issue like this but their main selling point appears to be that this isn't the case.