frontend – "custom attribute" is a required field Error Message – custom customer attribute to the user of the registry

Hello, I have added a custom customer attribute "Number" to my register page. Attribute was successfully created in DB.
My problem is when I submit the user registration request, the error message "customer number" is a mandatory field. is also displayed if the value is in the request text.
I implemented the frontend as follows

  1. Custom module created
  2. CustomModule / view / frontend / templates / additional.phtml added
  3. CustomModule / view / frontend / layout / customer_account_create.xml added

additional.phtml

<input type = "text" name = "kndnumber" id = "kndnumber" value = "" title = "escapeHtmlAttr (__ (& # 39; customer number & # 39;))?> "class =" input-text "data-validate =" {required: true} ">

customer_account_create.xml




    
        
            
        
    

Register user

The error is however displayed in the picture. The backend says the field is required, which is true because I want it that way. But I have the number in my request, why does the backend say that it's not that I do not get it.

Does anyone have any idea what the problem is?

This is the attribute in the table & # 39; # 39 & customer_eav_attribute;
exam