The documentation says that “radio buttons with the same name are mutually exclusive so they allow the user a single choice”. I need this in one of my forms: http://www.carola-scharvogel.de/anmeldung_trainer-plus.html
The first name fields do have same name, the second one specify the description and therefore are different.
When uploading it still allows to click and choose both.
Without the values filled in you can better see the fields:
The label is of course going to be different. The variable needs to be the same. Right now you have the variable “radio2” on one and “radio3” on the other.
The next problem is the mail form will say “Variable: Label” (replaced by the variable name you use and the label). So you need to have different labels to distinguish the option picked by the site visitor. For example you could have “TRAiNER+plus 28. Nov 2019” in one case, and “TRAiNER+plus 07. Mai 2020” in the other.
If you set the variable to be something meaningful like “package” for both, the form will work properly, and the email will be something like “package: TRAiNER+plus 28. Nov 2019” or “package: TRAiNER+plus 07. Mai 2020”.