This is less question and more of an FYI as I had this issue but have solved it and am sharing as there were't any resources I found here that helped with this issue.
BACKGROUND: Piloting Windows 10 and implementing new Security GPOs using Microsoft Security Compliance Manager (SCM).
ISSUE: Sophos Endpoint and Security Control was failing updates on Windows 10 after Windows 10 Security Baseline was applied.
LOG ENTRIES (alc.log):
Message: Could not connect to the server. Check that this computer is connected to the network and that Sophos is configured to update from the correct location with the correct credentials and proxy details (if required)
Message: Downloading product RMSNT from server \\Server\CID\...
Message: Could not add a connection to server \\Server\; user domain\account; Windows error 1312
RESOLUTION:
This GPO Setting: Network access: Do not allow storage of passwords and credentials for authentication" was enabled.
Computer Configuration/Policies/Windows Settings/Security Settings/Local Policies/Security Options
After changing the setting to not configured, Sophos began updating successfully.
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