diff --git a/Emby.Dlna/Ssdp/DeviceDiscovery.cs b/Emby.Dlna/Ssdp/DeviceDiscovery.cs
index 8c7d961f3e..d13871add8 100644
--- a/Emby.Dlna/Ssdp/DeviceDiscovery.cs
+++ b/Emby.Dlna/Ssdp/DeviceDiscovery.cs
@@ -69,7 +69,7 @@ namespace Emby.Dlna.Ssdp
         {
             lock (_syncLock)
             {
-                if (_listenerCount > 0 && _deviceLocator == null)
+                if (_listenerCount > 0 && _deviceLocator == null && _commsServer != null)
                 {
                     _deviceLocator = new SsdpDeviceLocator(_commsServer);
 
diff --git a/RSSDP/SsdpDeviceLocator.cs b/RSSDP/SsdpDeviceLocator.cs
index e2b524cf46..9a110683e5 100644
--- a/RSSDP/SsdpDeviceLocator.cs
+++ b/RSSDP/SsdpDeviceLocator.cs
@@ -27,14 +27,15 @@ namespace Rssdp.Infrastructure
         /// </summary>
         public SsdpDeviceLocator(ISsdpCommunicationsServer communicationsServer)
         {
+            if (communicationsServer == null)
+            {
+                throw new ArgumentNullException(nameof(communicationsServer));
+            }
+            
             _CommunicationsServer = communicationsServer;
 
-            if (communicationsServer != null)
-            {
-                // This can occur is dlna is enabled, but defined to run over https.
-                _CommunicationsServer.ResponseReceived += CommsServer_ResponseReceived;
-            }
-
+            // This can occur is dlna is enabled, but defined to run over https.
+            _CommunicationsServer.ResponseReceived += CommsServer_ResponseReceived;
             _Devices = new List<DiscoveredSsdpDevice>();
         }