Listing reserved IP-Adresses reveales if a Mailadress is used for an IP-Adress

```
Code
    400
Beschreibung
    Kein Eintrag für diese E-Mail 

```

The page you get redirected to [after asking for your IPs](https://config.berlin.freifunk.net/summary) should have a generic reply not revealing if an mailadress is used for freifunk.