In the update manager details you see the following error:
80040407 Delivery failed for software subscription [subscription-name]. Proxy is denying access or is otherwise unavailable.
First seen in Enterprise Console 4.0.0
Sophos Update Manager (SUM) generates this error if it cannot authenticate with a proxy server.
The most likely problem is that the path of the proxy server is incorrect, or its credentials are wrong. If the proxy has worked in the past, and nothing has been changed, then it could be a problem with network connectivity.
Correct any network connectivity problems and then attempt to download updates again (right-click an update manager and choose 'Update Now').
If you have tried all the steps above but updates are still failing check the Sophos Update Manager Logviewer.exe tool for a more detailed error. Search the knowledgebase for errors you see in the Logviewer.
If you are unable to find information in the knowledgebase regarding the errors shown:
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