Incorrect hardware health data often results from polling the wrong MIB tree. By changing to the correct or preferred MIB tree for the device model, SolarWinds can accurately interpret and display hardware health metrics.
Reference:
" If hardware health data is inaccurate, ensure the correct MIB tree is being used for polling. Selecting the appropriate MIB provides the most accurate sensor readings. "
- (Network Performance Monitor Administrator Guide, Hardware Health Troubleshooting section)

SolarWinds identifies and classifies flow traffic based on application and port mapping in the platform.
" Unclassified traffic in flow charts often occurs when an application is not mapped in the system, or when the application uses a port that is not defined in the SolarWinds Hybrid Cloud Observability (HCO) application mapping database. Flows from unsupported devices or flow direction do not cause unclassified application traffic-rather, they will not be collected or will be marked as unknown flows. " Thus, unclassified traffic can result from new or custom applications or changes in port usage that are not reflected in the configuration.
References:
Network Performance Monitor Administrator Guide, Section: " Flow Classification and Unclassified Traffic " SolarWinds Success Center: " How Flow Data Is Classified "

For objects assigned to an Additional Polling Engine, the main SolarWinds Platform server and Web Console must be able to resolve and communicate with the APE. SolarWinds scalability-engine guidance states that port 17777/TCP is used by the SolarWinds Information Service for bidirectional communication between the Additional Polling Engine and the main polling engine. If port 17777 is blocked on the APE, object editing and platform module communication can fail for objects owned by that APE. An invalid DNS entry for the APE can create the same practical problem because the main server cannot reliably reach the APE by name.
Port 5671 is RabbitMQ messaging and is important, but option C is the more direct fit for editing/access through Information Service.

SolarWinds NTA processes flow data via a dedicated collector component. Devices are configured to export flow records to the NTA collector, which ingests, stores, and analyzes the data.
" NetFlow Traffic Analyzer receives flow data from network devices using the NetFlow Collector service, which processes and stores traffic information for analysis. " No agent is required on target devices, and the collector is the key processing method.
References:
Network Performance Monitor Administrator Guide, Section: " How NTA Works " SolarWinds NTA Documentation

Comprehensive and Detailed Explanation From Exact Extract:
Universal Device Pollers (UDPs) must be explicitly assigned to each node for which custom polling is required. Adding a new node does not automatically assign existing UDPs to that node, even if it's the same device type as others already using the poller. Assigning the existing UDP to the new node will resolve the issue and enable polling of the desired data.
Reference:
Universal Device Poller Admin Guide, "Assigning UDPs to Nodes,"
"For custom OID polling, assign the UDP to each node individually..."