Index: binary-improvements/MapRendering/Web/Web.cs
===================================================================
--- binary-improvements/MapRendering/Web/Web.cs	(revision 282)
+++ binary-improvements/MapRendering/Web/Web.cs	(revision 286)
@@ -156,4 +156,10 @@
 						cookie.Secure = false;
 						response.AppendCookie (cookie);
+					}
+
+					// No game yet -> fail request
+					if (GameManager.Instance.World == null) {
+						response.StatusCode = (int)HttpStatusCode.ServiceUnavailable;
+						return;
 					}