Due to a bug in the handling of the Check_MK server response, a valid downloaded MSI-packaged agent updater can be mistaken as a "login failed" response.
Instead of updating the Windows Agent, the agent updater would display the error message "ERROR: Cannot authenticate, invalid user/passwort/secret." and abort.
In order to restore funtionality to the Agent Updater, please uninstall the Windows Agent on the affected hosts and reinstall with a newly baked MSI-package.
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