Network Management

Web Console extremely slow and "503 Service Unavailable" error displays after upgrade to SolarWinds Platform 2025.4

After upgrading to SolarWinds 2025.4, users may experience the website becoming slow, unresponsive, and displaying a "503 Service Unavailable" error. The SolarWinds Platform Website service may also be stopped.

First published date

12/1/2025 6:15 PM

Last published date

12/17/2025 3:44 PM

Overview

Following the upgrade to version 2025.4, the SolarWinds web interface can become unresponsive, with HTTP Error 503 displayed when loading views. Investigation shows that the IIS Application Pool for the SolarWinds Orion website is stopping unexpectedly. IIS logs indicate the application pool is recycling because it has reached its private bytes memory limit. 

A worker process serving the app pool has requested a recycle because it reached its private bytes memory limit.

Product section

Network Performance Monitor

Cause

The issue is related to memory limits configured in IIS for the SolarWinds Orion Application Pool. The upgrade to 64-bit mode increases memory usage, which can cause the application pool to hit the configured private memory limit and recycle frequently. By default, the private memory limit is set to 1.2 GB (1200000 KB), which may be insufficient for the 64-bit environment.


 

 

 

Resolution

  1. If you are still using Network Atlas Maps, enable 32-bit applications in the application pool:
    • Open IIS Manager.
    • Navigate to Application Pools.
    • Right-click SolarWinds Orion Application Pool and select Advanced Settings.
    • Set Enable 32-Bit Applications to True.

 

  1. Increase the private memory limit to accommodate higher memory usage:

    • In IIS Manager, open Advanced Settings for the SolarWinds Orion Application Pool.
    • Locate Private Memory Limit (KB) and increase it to 2400000 (2.4 GB) or 3600000 (3.6 GB), or set it to 0 to remove the limit entirely.

 

  1. Restart IIS components to apply changes:

    • Stop the SolarWinds Platform Website service.
    • Restart the SolarWinds Orion Application Pool.
    • Start the SolarWinds Platform Website service again.