Index: openacs-4/packages/chat/tcl/chat-ajax-procs.tcl
===================================================================
RCS file: /usr/local/cvsroot/openacs-4/packages/chat/tcl/chat-ajax-procs.tcl,v
diff -u -N -r1.12.2.6 -r1.12.2.7
--- openacs-4/packages/chat/tcl/chat-ajax-procs.tcl	1 Dec 2016 17:56:59 -0000	1.12.2.6
+++ openacs-4/packages/chat/tcl/chat-ajax-procs.tcl	4 Apr 2017 14:52:59 -0000	1.12.2.7
@@ -124,7 +124,9 @@
 	{-uid ""}
 	msg
     } {
-	:check_valid_room
+	if {![chat_room_exists_p [:chat_id]]} {
+	    return
+	}
 
 	# ignore empty messages
 	if {$msg eq ""} return