Addon data missing for product

When I design a product and put it in the shopping cart, I suddenly get this error message:

Addon data missing for product Bauchbinde Format 1
up until now everything worked without errors.
can’t find the error, where should I look?

thank you very much for your help.

best regards
Renato

Are you using WooCommerce Product Add-Ons or a similar plugin? This error could be caused by improperly configured product add-ons or missing required information. Go to the product in the WooCommerce admin area & ensure that all required fields in the product’s addon configuration are filled out correctly.

It’s best to contact the author of the item you’re using.