diff --git a/luprex/cpp/core/lpxserver.cpp b/luprex/cpp/core/lpxserver.cpp
index de834774..5b191e0d 100644
--- a/luprex/cpp/core/lpxserver.cpp
+++ b/luprex/cpp/core/lpxserver.cpp
@@ -251,6 +251,7 @@ public:
             
             // Check for received invocations.
             while (handle_invocation(client));
+            if (client == nullptr) continue;
 
             // Possibly send a diff.
             double diffdelay = 5.0;