Applications Systems

WMI Test Fails with "RPC Server Is Unavailable" When Adding Windows Nodes in SolarWinds Platform

When attempting to add Windows servers to SolarWinds Platform monitoring using WMI, the node addition may fail with Test Failed or Test Job Timeout errors. In some cases, performing a manual WMI test using WBEMTEST returns the error "RPC Server is unavailable" (0x800706ba) when connecting via IP address, while connections using the hostname succeed.

First published date

1/5/2026 5:07 PM

Last published date

1/7/2026 4:13 PM

Overview

If Windows servers cannot be added to SolarWinds via WMI and return an "RPC Server is unavailable" error, the issue is typically related to DNS resolution, RPC port accessibility, or Windows service configuration. Validate connectivity using WBEMTEST, confirm DNS accuracy, and ensure required RPC/WMI ports are allowed. Once WBEMTEST succeeds, SolarWinds WMI monitoring will function correctly.

Product section

Server Application Monitor

Cause

This is caused by incorrect or stale DNS/reverse-DNS records and/or firewall rules that do not fully allow RPC dynamic ports (TCP 135 and the dynamic high port range) for IP-based connections.

Resolution

Resolution:

The most common issue causing ‘RPC Server Not Available’ is related to the TCP/UDP ports that certain Windows subsystems require for gathering performance data from remote servers. These ports are as follows:

  • WMI Access:
  • TCP port 135 and a range of dynamic ports, [TCP 49152-65535 (RPC dynamic ports – Windows Vista, 2008 and above), TCP 1024-65535 (RPC dynamic ports – Windows NT4, Windows 2000, Windows 2003), or a custom range of ports (see note below)]
  • Widows Performance Counter Access: TCP port 445 (SMB, RPC/NP)
  • There are other reasons that you might have trouble gathering performance data, but the inability to connect via the above ports is known to cause the ‘RPC server Not Available’ error specifically.

 

Verify DNS Resolution and Fix Stale DNS Records

  1. From the SolarWinds Poller, open Command Prompt.
  2. Run the following commands:
    • nslookup <hostname>
    • ping <hostname>
  3. Ensure the hostname resolves to the correct IP address.
  4. If incorrect or outdated IPs are returned:
    • Flush DNS cache using ipconfig /flushdns
    • Correct stale DNS records on the DNS server

WMI over RPC is highly dependent on DNS. IP-based WMI connections may fail while hostname-based connections succeed.

Test WMI Connectivity Using WBEMTEST

  1. On the SolarWinds Poller, press Win + R, type wbemtest, and click OK.
  2. Click Connect.
  3. Enter the namespace:
    \\<TargetServerHostname>\root\cimv2
  4. Click Connect.
  5. If the connection succeeds:
    • Click Enum Classes or Query to confirm WMI functionality

If WBEMTEST fails with "RPC Server is unavailable", SolarWinds WMI polling will also fail.

 

Once DNS is corrected and the required RPC/WMI ports are open from the poller to the server, WBEMTEST succeeds, and SolarWinds WMI monitoring works normally.

Please note: WBEMTEST is a non-Solarwinds tool, a built-in Windows utility that acts as a graphical interface to Windows Management Instrumentation (WMI), allowing users to test WMI connectivity, query WMI data, and troubleshoot management issues. Do you have any WMI nodes assigned to the same poller? If yes, it means that the Solarwinds poller can communicate properly using the WMI method. We highly recommend checking this with Microsoft, the Network and Security team to validate the server configuration, network, and security settings.

You can also visit the link below for additional information. 

https://learn.microsoft.com/en-us/troubleshoot/windows-server/user-profiles-and-logon/not-log-on-error-rpc-server-unavailable