There was an unexpected error (type=Internal Server Error, status=500). An error happened during template parsing [closed]

Closed 4 hours ago.

There was an unexpected error (type=Internal Server Error, status=500). An error happened during template parsing [closed]

Closed 4 hours ago.

Thymeleaf form not saving data to database for nested objects in Spring Boot

I don’t understand why the entered data from the html template is not saved in the database.