diff --git a/CoreRemoting/RemotingSession.cs b/CoreRemoting/RemotingSession.cs
index 028bb52..43e181f 100644
--- a/CoreRemoting/RemotingSession.cs
+++ b/CoreRemoting/RemotingSession.cs
@@ -122,6 +122,9 @@ internal RemotingSession(int keySize, byte[] clientPublicKey, IRemotingServer se
             _remoteDelegateInvocationEventAggregator.RemoteDelegateInvocationNeeded +=
                 (_, uniqueCallKey, handlerKey, arguments) =>
                 {
+                    if (_isDisposing)
+                        return null;
+
                     var sharedSecret =
                         MessageEncryption
                             ? _sessionId.ToByteArray()