invalid mailbox syntax by using hidden field

I have defined in my contact form 7 formular a hidden field which should be assigned a dynamic email adress. I initialized the hidden field like this:

[hidden your-email default:user_email “[email protected]”]

In the “To” field of the email I conficured it like: [your-email]

After saving it an error occured: invalid mailbox syntax used!

I do not understand why this error occured. Who knows how I can use a hidden dynamic email field in the “To” field of the email send adress?

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