Errors in NS logs: Data encryption for resource was requested, but encryption key is missing, COM Exception: 0x80077000

Products

• Management Platform (Formerly known as Notification Server)

Issue/Introduction

The NS logs are flooded with errors regarding encryption keys and client computer guids

Data encryption for resource was requested, but encryption key is missing: COMPUTER-GUID-GUID-GUID-GUIDGUIDGUID
Unable to process session message: COMPUTER-GUID-GUID-GUID-GUIDGUIDGUID
<msg type="EndpointTrustInfo" guid="6939ee4b-2493-434f-9bd6-b077a224c870" />

Failed to load agent encryption key.
…
COM Exception errcode: 0x80077000

Cause

Possible corruption of the Task Server

Environment

ITMS 7.6 and later

Resolution

In one case this was resolved by uninstalling and reinstalling (or upgrading) Task Service on the Site Servers the problem computers were assigned to. The problem computers can be identified GUID's shown in the errors.

As well there are NS log entries showing the IP address of such machines, like this one:

Policy request failed from: 192.68.72.197
Failed to load agent encryption key.​