diff --git a/src/libraries/System.Net.Quic/src/System/Net/Quic/Implementations/MsQuic/Interop/SafeMsQuicConfigurationHandle.cs b/src/libraries/System.Net.Quic/src/System/Net/Quic/Implementations/MsQuic/Interop/SafeMsQuicConfigurationHandle.cs
index 24200021ec0546..d536dfa58dbdcc 100644
--- a/src/libraries/System.Net.Quic/src/System/Net/Quic/Implementations/MsQuic/Interop/SafeMsQuicConfigurationHandle.cs
+++ b/src/libraries/System.Net.Quic/src/System/Net/Quic/Implementations/MsQuic/Interop/SafeMsQuicConfigurationHandle.cs
@@ -156,9 +156,13 @@ private static unsafe SafeMsQuicConfigurationHandle Create(QuicOptions options,
                 ulong ms = (ulong)options.IdleTimeout.Ticks / TimeSpan.TicksPerMillisecond;
                 if (ms > (1ul << 62) - 1) throw new Exception("IdleTimeout is too large (max 2^62-1 milliseconds)");
 
-                settings.IsSetFlags |= QuicSettingsIsSetFlags.IdleTimeoutMs;
                 settings.IdleTimeoutMs = (ulong)options.IdleTimeout.TotalMilliseconds;
             }
+            else
+            {
+                settings.IdleTimeoutMs = 0;
+            }
+            settings.IsSetFlags |= QuicSettingsIsSetFlags.IdleTimeoutMs;
 
             uint status;
             SafeMsQuicConfigurationHandle? configurationHandle;