<behaviors>
      <serviceBehaviors>
        <behavior name="CustomerWebServiceBehavior">
          <serviceMetadata httpGetEnabled="true" httpsGetEnabled="false" />
          <serviceCredentials>
            <clientCertificate>
              <certificate findValue="ServerGestionale" storeLocation="CurrentUser"
                storeName="My" x509FindType="FindBySubjectName" />
            </clientCertificate>
            <serviceCertificate findValue="ServerGestionale" storeLocation="CurrentUser"
              x509FindType="FindBySubjectName" />
            <userNameAuthentication userNamePasswordValidationMode="Custom"
              customUserNamePasswordValidatorType="Techsol.Gestionale.Services.UserValidator, Techsol.Gestionale.Services" />
          </serviceCredentials>
        </behavior>
      </serviceBehaviors>
    </behaviors>

    <bindings>
      <wsHttpBinding>
        <binding name="UserNameBinding" maxReceivedMessageSize="524288">
          <security>
            <transport clientCredentialType="Certificate" />
            <message clientCredentialType="UserName" />
          </security>
        </binding>
      </wsHttpBinding>
    </bindings>

The X.509 certificate CN=ServerGestionale is not in the trusted people store. The X.509 certificate CN=ServerGestionale chain building failed. The certificate that was used has a trust chain that cannot be verified. Replace the certificate or change the certificateValidationMode. The revocation function was unable to check revocation for the certificate.

<system.serviceModel>
        <behaviors>
            <endpointBehaviors>
                <behavior name="ClientCredentialsBehavior">
                    <clientCredentials>
                        <clientCertificate findValue="ServerGestionale" storeName="TrustedPeople"
                            x509FindType="FindBySubjectName" />
                        <serviceCertificate>
                            <authentication certificateValidationMode="PeerOrChainTrust" />
                        </serviceCertificate>
                    </clientCredentials>
                </behavior>
            </endpointBehaviors>
        </behaviors>
        <bindings>
            <wsHttpBinding>
                <binding name="HTTPWebService" closeTimeout="00:01:00" openTimeout="00:01:00"
                    receiveTimeout="00:10:00" sendTimeout="00:01:00" bypassProxyOnLocal="false"
                    transactionFlow="false" hostNameComparisonMode="StrongWildcard"
                    maxBufferPoolSize="524288" maxReceivedMessageSize="524288"
                    messageEncoding="Text" textEncoding="utf-8" useDefaultWebProxy="true"
                    allowCookies="false">
                    <readerQuotas maxDepth="32" maxStringContentLength="8192" maxArrayLength="16384"
                        maxBytesPerRead="4096" maxNameTableCharCount="16384" />
                    <reliableSession ordered="true" inactivityTimeout="00:10:00"
                        enabled="false" />
                    <security mode="Message">
                        <transport clientCredentialType="Certificate" proxyCredentialType="None"
                            realm="" />
                        <message clientCredentialType="UserName" negotiateServiceCredential="true"
                            algorithmSuite="Default" establishSecurityContext="true" />
                    </security>
                </binding>
            </wsHttpBinding>
        </bindings>
        <client>
            <endpoint address="http://localhost:8731/Design_Time_Addresses/Techsol.Gestionale.WebServices/CostumerWebService/"
                behaviorConfiguration="ClientCredentialsBehavior" binding="wsHttpBinding"
                bindingConfiguration="HTTPWebService" contract="CustomerServiceReference.ICustomerServices"
                name="HTTPWebService">
                <identity>
                    <dns value="localhost" />
                    <certificateReference storeName="TrustedPeople" storeLocation="CurrentUser"
                        x509FindType="FindBySubjectName" findValue="ServerGestionale" />
                </identity>
            </endpoint>
        </client>
    </system.serviceModel>

Identity check failed for outgoing message. The expected DNS identity of the remote endpoint was 'localhost' but the remote endpoint provided DNS claim 'ServerGestionale'. If this is a legitimate remote endpoint, you can fix the problem by explicitly specifying DNS identity 'ServerGestionale' as the Identity property of EndpointAddress when creating channel proxy.

Secure channel cannot be opened because security negotiation with the remote endpoint has failed. This may be due to absent or incorrectly specified EndpointIdentity in the EndpointAddress used to create the channel. Please verify the EndpointIdentity specified or implied by the EndpointAddress correctly identifies the remote endpoint.