diff --git a/Pilz.Net/Api/ApiServer.cs b/Pilz.Net/Api/ApiServer.cs
index e24f0c3..b15979b 100644
--- a/Pilz.Net/Api/ApiServer.cs
+++ b/Pilz.Net/Api/ApiServer.cs
@@ -98,7 +98,7 @@ public class ApiServer(string apiUrl) : IApiServer
 
     protected virtual void WaitForSlot()
     {
-        if (MaxConcurentConnections == int.MaxValue)
+        if (!AllowMultipleRequests)
             return; // Unlimited in this case
         semaphore ??= new(MaxConcurentConnections, MaxConcurentConnections);
         semaphore.Wait();
@@ -257,7 +257,10 @@ public class ApiServer(string apiUrl) : IApiServer
 
         // Listen for new request
         if (!AllowMultipleRequests)
+        {
+            FreeSlot();
             Receive();
+        }
     }
 
     protected virtual void CheckContext(HttpListenerContext context)