'Invalid certificate' on send - re-bind CAC to Windows

windows

Symptoms

Outlook returns 'Invalid certificate' when sending.

Likely cause

Cert handle dropped between ActivClient and Windows.

Fix

1. Remove and reinsert the CAC, then retry. 2. Or open ActivClient > right-click My Certificates > Make Certificates Available to Windows, then retry.

Sourced from militarycac.com. Rewritten for clarity.

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