Netconf-console error using augmentation

I am adding an augmentation to a module and I get the following error when trying to edit-config/create using the netconf-console.

My augmentation compiles correctly and I can pull the schema via netconf-console --get-schema`

Why does it fail when I try to create an entry?

XML for edit-config/create

<my-prefix:my-aug>123</my-prefix:my-aug>

Error
<?xml version="1.0" encoding="UTF-8"?>
<rpc-reply xmlns="urn:ietf:params:xml:ns:netconf:base:1.0" message-id="1">
<rpc-error>
<error-type>rpc</error-type>
<error-tag>operation-failed</error-tag>
<error-severity>error</error-severity>
...
<error-message xml:lang="en">'my-prefix' is an unknown prefix.</error-message>
<error-info>
<bad-element>my-element</bad-element>
</error-info>
</rpc-error>
</rpc-reply>
unexpected EOF in NETCONF transport

Just in case anyone else runs into this…

Needed to add the xmlns to resolve prefix

xmlns:my-prefix="…"