REST API: errors {:email "value must be a valid email address."}

Hello to everyone,
I am trying to preconfigure a new metabase setup using the REST api. Metabase gives the error: DEBUG middleware.log :: POST /api/setup 400 13.2 ms (0 DB calls) {:errors {:email "value must be a valid email address."}}. I tried with

"email":"firstname.lastname%40my-company.de"
and
"email":"firstname.lastname@my-company.de"

What am I doing wrong?

Best regards
Thomas

Hi @q5616417
Which version of Metabase?
You’re using this endpoint? https://github.com/metabase/metabase/blob/master/docs/api-documentation.md#post-apisetup
Just making sure that it’s the forum formatting and not your input that contains the incorrect quotation marks ("), right?
Does the address contain anything besides a-z\.\- ? Umlaut or other non-international characters.
If you traffic sniff the request, you might be able to spot the problem easier.