XmlSchemaException C#

I have to read an XML from file, which is:

<?xml version="1.0" encoding="UTF-16"?>
   <KyactusProfileClass xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
      <username>sadasdsad</username> 
      <userid>0067AA87BF9AD466792E1A20F6AAB7F</userid>
      <useDefaultFolder>false</useDefaultFolder>
      <autoAcceptDownloads>false</autoAcceptDownloads>
      <visible>false</visible>
   </KyactusProfileClass>

I read it using following code:

using (var xmlReader = XmlReader.Create(pathXML))
{
    Console.WriteLine(File.ReadAllText(pathXML));
    schemas.Add(null, xmlReader);
}

But I get following error:

System.Xml.Schema.XmlSchemaException: 'The root element of W3C XML Schema must be < schema > and its namesapce must be 'http://www.w3.org/2001/XMLSchema'.'

I generated that XML using a XML serializer and XSD Schema validator:

<xs:schema attributeFormDefault="unqualified" elementFormDefault="qualified"
           xmlns:xs="http://www.w3.org/2001/XMLSchema">
  <xs:element name="kyactusprofile" type="kyactusprofile" />
  <xs:complexType name="kyactusprofile" >
    <xs:sequence>
    <xs:element type="xs:string" name="username" maxOccurs="1" minOccurs="1"/>
    <xs:element type="xs:string" name="userid"  maxOccurs="1" minOccurs="1"/>
    <xs:element type="xs:boolean" name="useDefaultFolder"  maxOccurs="1" minOccurs="1"/>
    <xs:element type="xs:string" name="defaultFolder"  maxOccurs="1" minOccurs="1"/>
    <xs:element type="xs:boolean" name="autoAcceptDownloads"  maxOccurs="1" minOccurs="1"/>
    <xs:element type="xs:boolean" name="visible"  />
    </xs:sequence>
  </xs:complexType>
</xs:schema>

Hers is the stack trace:

System.Xml.Schema.XmlSchemaException
  HResult=0x80131941
  Message=L'elemento radice di W3C XML Schema deve essere <schema> e il suo spazio dei nomi deve essere 'http://www.w3.org/2001/XMLSchema'.
  Source=System.Xml
  StackTrace:
   at System.Xml.Schema.XmlSchemaSet.InternalValidationCallback(Object sender, ValidationEventArgs e)
   at System.Xml.Schema.XmlSchemaSet.SendValidationEvent(XmlSchemaException e, XmlSeverityType severity)
   at System.Xml.Schema.XmlSchemaSet.ParseSchema(String targetNamespace, XmlReader reader)
   at System.Xml.Schema.XmlSchemaSet.Add(String targetNamespace, XmlReader schemaDocument)
   at Kyactus.XmlManager.GestoreXml.ValidateXmlWithXsd(String pathXML) in C:\Users\Cristiano\Documents\Visual Studio 2017\Projects\progetto-pds\visual-studio\Kyactus\Kyactus\XmlManager\GestoreXml.cs:line 249
   at Kyactus.XmlManager.GestoreXml.UnmarshallProfile() in C:\Users\Cristiano\Documents\Visual Studio 2017\Projects\progetto-pds\visual-studio\Kyactus\Kyactus\XmlManager\GestoreXml.cs:line 178
   at Kyactus.XmlManager.GestoreXml..ctor() in C:\Users\Cristiano\Documents\Visual Studio 2017\Projects\progetto-pds\visual-studio\Kyactus\Kyactus\XmlManager\GestoreXml.cs:line 64
   at Kyactus.App..ctor() in C:\Users\Cristiano\Documents\Visual Studio 2017\Projects\progetto-pds\visual-studio\Kyactus\Kyactus\App.xaml.cs:line 21
   at Kyactus.App.Main()

You are most likely reading the XML

<?xml version="1.0" encoding="UTF-16"?>
   <KyactusProfileClass xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
      <username>sadasdsad</username> 
      <userid>0067AA87BF9AD466792E1A20F6AAB7F</userid>
      <useDefaultFolder>false</useDefaultFolder>
      <autoAcceptDownloads>false</autoAcceptDownloads>
      <visible>false</visible>
   </KyactusProfileClass>

with the XmlReader and try to add it as XmlSchema. That's the wrong approach, it's not a schema! You have to read your XSD, then no Exception will appear.