Add Request POST using REST API

I'm trying to POST to ServiceDesk Plus MSP with test data as follows:

<Operation>
<Details>
<requester>Test Requester</requester>
<subject>Test Subject</subject>
<description>Testing Curl POST</description>
<callbackURL> http://localhost:8080/CustomReportHandler.do</callbackURL>
<requestType>Incident</requestType>
<requesttemplate>Monitoring and Data Analytics Alarm</requesttemplate>
<priority>High</priority>
<site>Test Site</site>
<account>Test Account</account>
<group>Test Group</group>
<status>Open</status>
</Details>
</Operation>

The specified template does exist. The full URL is as follows:

http://localhost:8080/sdpapi/request/?OPERATION_NAME=ADD_REQUEST&TECHNICIAN_KEY=XXXXXXXX-XXXX-XXXX-XXXX-XXXXXXXXXXXX&INPUT_DATA=<Operation><Details><requester>Test Requester</requester><subject>Test Subject</subject><description>Testing Curl POST</description><callbackURL> http://localhost:8080/CustomReportHandler.do</callbackURL><requestType>Incident</requestType><requesttemplate>Monitoring and Data Analytics Alarm</requesttemplate><priority>High</priority><site>Test Site</site><account>Test Account</account><group>Test Group</group><status>Open</status></Details></Operation>

I receive the following error:

This XML file does not appear to have any style information associated with it. The document tree is shown below.
<API version="1.0">
<response>
<operation name="GET">
<result>
<status>Failed</status>
<message>
User does not have permissions to view this request filter
</message>
</result>
</operation>
</response>
</API>

Can I have an example of the most basic rest api post request example to add an incident with the following: Site, Account, Requester Name, Subject, Description.