xml-xsd validation debugging

Working in xml xsd for the first time. I have the xsd and xml data as below. When I try to validate I get error. Code and Error below.

Please help me finding on whats going wrong.

XSD:

 <?xml version="1.0" encoding="UTF-8"?>
<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema" xmlns:tns="http://www.m5net.com/mantle/configuration/connectors" elementFormDefault="qualified" targetNamespace="http://www.m5net.com/mantle/configuration/connectors">
   <xs:complexType name="ShoretelCosmoConference">
      <xs:complexContent mixed="false">
         <xs:extension base="tns:Configuration">
            <xs:sequence>
               <xs:element minOccurs="0" name="AccountId" nillable="true" type="xs:int" />
               <xs:element minOccurs="0" name="StartConference" nillable="true" type="xs:string" />
               <xs:element minOccurs="0" name="EndConference" nillable="true" type="xs:string" />
               <xs:element minOccurs="0" name="WebLoginMode" nillable="true" type="xs:string" />
               <xs:element minOccurs="0" name="Password" nillable="true" type="xs:string" />
               <xs:element minOccurs="0" name="OutdialPrompt" type="xs:boolean" />
               <xs:element minOccurs="0" name="NotifyChanges" type="xs:boolean" />
               <xs:element minOccurs="0" name="NotificationEmail" nillable="true" type="xs:string" />
            </xs:sequence>
         </xs:extension>
      </xs:complexContent>
   </xs:complexType>
   <xs:element name="ShoretelCosmoConference" nillable="true" type="tns:ShoretelCosmoConference" />
</xs:schema>

XML :

<?xml version="1.0" encoding="UTF-8"?>
<ShoretelCosmoConference xmlns="http://www.m5net.com/mantle/configuration/connectors" xmlns:i="http://www.w3.org/2001/XMLSchema-instance">
   <AccountId>13284</AccountId>
   <EndConference>Moderator leaves</EndConference>
   <NotificationEmail />
   <NotifyChanges>false</NotifyChanges>
   <OutdialPrompt>true</OutdialPrompt>
   <Password />
   <StartConference>Host Joins</StartConference>
   <WebLoginMode>Name Only</WebLoginMode>
</ShoretelCosmoConference>

Error :

XML Validation: Unexpected element(s): {http://www.m5net.com/mantle/configuration/connectors}NotifyChanges. Location: /:ShoretelCosmoConference[1]/:NotifyChanges[1]