Repeater Field not working

i built a event subscription form and want to use the repeater field for participant name and email.

i configured the field like in your documentation video and the frontend works fine so far.

the problem is that the email i get does not include the data from the fields i entered in frontend.

only the tags are shown in mail like [participant_name] and [participant_email]

all the other fields (non repeater CF7 default fields) are working fine.

Contact Form 7: 5.7.7
Ultimate Addons for Contact Form 7: 3.1.28
Ultimate Addons for Contact Form 7 Pro: 1.5.3
UACF7 Addon – Repeater Field: 1.1.10

thanks for your help