Not able to reconfigure VM for mutiple section

I have tried to make a POST request as per the example ( https://pubs.vmware.com/vca/index.jsp#com.vmware.vcloud.api.doc_56/GUID-4759B018-86C2-4C91-8176-3EC73CD7122B.html ) to update multiple sections of the VM. But i always get error 415

I always get the below error even if i try to update atleast one section, like either "name and description" or just "network connection section"

<?xml version="1.0" encoding="UTF-8"?>

<Error xmlns="http://www.vmware.com/vcloud/v1.5" majorErrorCode="415" message="Unsupported Media Type" minorErrorCode="UNSUPPORTED_MEDIA_TYPE" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.vmware.com/vcloud/v1.5http://vcloud-url/api/v1.5/schema/master.xsd"></Error>

Is it possible to do "reconfigureVM" action request ? and if yes, could anyone help with updating vm name and network section

Note: I can do PUT request to update each section separately.

And yes the "test_vapp1-network" in Network Section in below XML which is the vapp network name does exist.

Here is my XML:

<?xml version="1.0" encoding="UTF-8"?><Vm xmlns="http://www.vmware.com/vcloud/v1.5"     name="test_vm_1">     <Description>A test VM</Description>    <NetworkConnectionSection          type="application/vnd.vmware.vcloud.networkConnectionSection+xml"        xmlns="http://www.vmware.com/vcloud/v1.5"        xmlns:ovf="http://schemas.dmtf.org/ovf/envelope/1">        <ovf:Info>Firewall allows access to this address.</ovf:Info>        <PrimaryNetworkConnectionIndex>0</PrimaryNetworkConnectionIndex>        <NetworkConnection            network="test_vapp1-network">            <NetworkConnectionIndex>0</NetworkConnectionIndex>            <IsConnected>true</IsConnected>            <IpAddressAllocationMode>POOL</IpAddressAllocationMode>        </NetworkConnection>    </NetworkConnectionSection>     <GuestCustomizationSection      xmlns="http://www.vmware.com/vcloud/v1.5"      xmlns:ovf="http://schemas.dmtf.org/ovf/envelope/1"      ovf:required="false">      <ovf:Info>Specifies Guest OS Customization Settings</ovf:Info>      <Enabled>true</Enabled>      <ChangeSid>true</ChangeSid>      <VirtualMachineId>hddhdhdhd</VirtualMachineId>      <AdminPasswordEnabled>true</AdminPasswordEnabled>      <AdminPassword>test123456</AdminPassword>      <ResetPasswordRequired>false</ResetPasswordRequired>      <CustomizationScript />      <ComputerName>test_vm_1</ComputerName>    </GuestCustomizationSection></Vm>