Pretty much what it says on the tin. I tried to unsubscribe using the link in the email I received today and was taken to a missing page. Link in the email was https://telescopius.com/en/notifications/new-moon-unsubscribe/[30-character hexadecimal id omitted].
Ohh thank you for reporting this, I’m fixing it for the next release. This is related to a change I did to the language prefixes, nasty side effect. Thanks again!