Netconf "unknown-element" reply for "mdt-config-data" element

[barl3yb3ar]

I'm trying to set the Cisco CAT-9K config (IOS-XE 17.3) using Netconf, but I get the "unknown-element" response for the "mdt-config-data" element:

The RPC XML request looks fine to me (matches Blog examples and 17.3 yang models):

<?xml version="1.0" encoding="UTF-8"?>
<rpc xmlns="urn:ietf:params:xml:ns:netconf:base:1.0" message-id="101">
  <edit-config>
    <target>
      <running />
    </target>
    <config xmlns:xc="urn:ietf:params:xml:ns:netconf:base:1.0">
      <mdt-config-data xmlns="http://cisco.com/ns/yang/Cisco-IOS-XE-mdt-cfg">
        <mdt-subscription>
          <subscription-id>200</subscription-id>
          <base>
            <stream>yang-push</stream>
            <encoding>encode-kvgpb</encoding>
            <period>6000</period>
            <xpath>/memory-ios-xe-oper:memory-statistics/memory-statistic</xpath>
          </base>
          <mdt-receivers>
            <address>10.1.2.3</address>
            <port>5555</port>
            <protocol>grpc-tcp</protocol>
          </mdt-receivers>
        </mdt-subscription>
      </mdt-config-data>
    </config>
  </edit-config>
</rpc>]]>]]>

Error RPC Reply:

<?xml version="1.0" encoding="UTF-8"?>
<rpc-reply xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
  <rpc-error>
    <error-type>rpc</error-type>
    <error-tag>unknown-element</error-tag>
    <error-severity>error</error-severity>
    <error-info>
      <bad-element>mdt-config-data</bad-element>
    </error-info>
  </rpc-error>
</rpc-reply>]]>]]>

Any idea what could be causing this???

Thanks! Mark