Where can I register a case sensitive mailbox ([email protected])?

Question

Email

99% of mail services make email addresses case insensitive where [email protected] = [email protected]
I need a service where I can register a case sensitive mailbox so that [email protected] is not equal to

[email protected] if anyone suddenly knows where you can register a mailbox with the German letter ß in the domain part ([email protected]ßner.de)? And with ä ö ü umlauts, too, where can I get a box?

Answer 1

In another galaxy. Where are other rfcs https://tools.ietf.org/html/rfc5322

Answer 2

There are no case-sensitive mailboxes.
As for the "escet" and umlauts - this is most likely for you to a German-speaking registrar - there is probably a zone similar to .rf