Error message received when trying to log in using two-factor authentication:
"Defender cannot log you on now because the Defender Security Server is not available and you have no cached token data."
This could be due to Access Node configuration, Desktop Login configuration, or a combination of both. It may also indicate the required port isn't available, i.e., network issues.
Verify that the Access Node in use is configured properly: the user attempting to login must be a member, and the IP Subnet must allow for the system/device they're attempting to log in through.
Also verify that the Access Node port and shared secret is correct from the Desktop Login configuration (this is also valid from a VPN setup when RADIUS settings are configured.). Also confirm the Defender Servers configured within Defender Desktop Login are correct and available (has an IP of a Defender Security Server recently changed?)
The user must be assigned a token as well.
Verify that the port being used by the Access Node (the default is 1812) is available from the client.