diff --git a/dotnet/src/webdriver/NetworkManager.cs b/dotnet/src/webdriver/NetworkManager.cs
index 8d91b72bc27b0..7d3131c7a6114 100644
--- a/dotnet/src/webdriver/NetworkManager.cs
+++ b/dotnet/src/webdriver/NetworkManager.cs
@@ -45,7 +45,7 @@ public NetworkManager(IWebDriver driver)
             this.session = new Lazy<DevToolsSession>(() =>
             {
                 IDevTools devToolsDriver = driver as IDevTools;
-                if (session == null)
+                if (devToolsDriver == null)
                 {
                     throw new WebDriverException("Driver must implement IDevTools to use these features");
                 }