Comprehensive and Detailed Explanation From Exact Extract:
If logs are not being sent from a Windows agent, you must confirm that the log forwarding feature is enabled.
Even if the agent is installed, logs will not be transmitted unless this setting is turned on.
The documentation notes:
"Ensure the agent is configured to forward logs. Log forwarding must be enabled for the agent to transmit log data to the SolarWinds platform." References:
Log Analyzer Administrator Guide: Agent Log Forwarding Configuration

If the flow source view in SolarWinds NTA shows "never received" and firewall issues are ruled out, it is often because the device (node) is no longer monitored by SolarWinds. If a node is removed or its monitoring is disabled, the collector will not associate incoming flows from that node, resulting in " never received " status.
Reference:
" If a node is no longer monitored in SolarWinds, the NTA will not process any flows received from that node, and the flow source view will display ' never received ' . "
- (Network Performance Monitor Administrator Guide, NetFlow Troubleshooting and Monitoring Status section)

Comprehensive and Detailed Explanation From Exact Extract:
To detect duplex mismatches:
The node must be monitored (i.e., managed in SolarWinds).
The node must be in "up" status, so SNMP data about interface status, speed, and errors can be polled and compared.
Description in MIB (A) is not necessary if the device is already SNMP-capable, and "warning" status (C) is a result, not a requirement.
Reference:
NPM Administrator Guide, "Requirements for Detecting Duplex Mismatches,"
"Only monitored and up-status nodes are eligible for duplex mismatch detection."