[facet 'enumeration'] The value is not an element of the set

A value that is not on the schema's list of allowed values.

The message, as the validator reports it

Element 'status': [facet 'enumeration'] The value 'closed' is not an element of the set {'open', 'paid'}.

Why it happens

A code that is not in the code list: a country, currency or unit code, a status.
A different letter case, or surrounding spaces: the comparison is exact for string types.

How to fix it

Use one of the values listed in the message. A follow-up message about the type (is not a valid value of the local atomic type) is the same error and disappears with it.

Example

Validated against order.xsd, below.

Reports the error

<order currency="EUR">
  <id>A-1</id>
  <qty>1</qty>
  <status>closed</status>
</order>

Fixed

<order currency="EUR">
  <id>A-1</id>
  <qty>1</qty>
  <status>paid</status>
</order>

order.xsd

<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema">
  <xs:element name="order">
    <xs:complexType>
      <xs:sequence>
        <xs:element name="id" type="xs:string"/>
        <xs:element name="qty" type="xs:int"/>
        <xs:element name="status" type="Status" minOccurs="0"/>
        <xs:element name="code" type="Code" minOccurs="0"/>
        <xs:element name="note" type="Short" minOccurs="0"/>
      </xs:sequence>
      <xs:attribute name="currency" type="xs:string" use="required"/>
    </xs:complexType>
  </xs:element>
  <xs:simpleType name="Status">
    <xs:restriction base="xs:string">
      <xs:enumeration value="open"/>
      <xs:enumeration value="paid"/>
    </xs:restriction>
  </xs:simpleType>
  <xs:simpleType name="Code">
    <xs:restriction base="xs:string">
      <xs:pattern value="[A-Z]{3}-[0-9]{4}"/>
    </xs:restriction>
  </xs:simpleType>
  <xs:simpleType name="Short">
    <xs:restriction base="xs:string">
      <xs:maxLength value="10"/>
    </xs:restriction>
  </xs:simpleType>
</xs:schema>