Symptoms
Using curl -d@pem.removeSubscription.xml http://127.0.0.1:8440 to delete a subscription with a VPS that has the underscore symbol ( _ ) in its hostname, an error: "Failed to encode 'host_name': error code 300" appears.
Cause
Operations Automation allows to use underscore symbol ( _ ) in Windows VPS hostname. This behaviour is caused by a known software related issue #POA-99378.
Resolution
Please contact Odin Technical Support.