Hmm interesting situation. Do you know system used in Dropbox? You recommend Dropbox to any user over his email, he install dropbox and needs to login to dropbox. But he have to login with same account (email) you send to. If not, you won't get any extra space. And here it is same. On our server is information that balloni invited new user with email X. And when this user login to Store, you get LC. Anyway situation that user login to store with different email account then you used, is probably unsolvable. Or at least I have no idea how to solve it

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Emails are send in language you use in Locus, so you probably do not use DE in Locus, is it possible? Emails ending with "de" should be send in DE, agree, thanks.