Index: openacs-4/packages/acs-authentication/tcl/authentication-procs.tcl
===================================================================
RCS file: /usr/local/cvsroot/openacs-4/packages/acs-authentication/tcl/authentication-procs.tcl,v
diff -u -r1.89.2.15 -r1.89.2.16
--- openacs-4/packages/acs-authentication/tcl/authentication-procs.tcl	16 Jun 2017 17:07:03 -0000	1.89.2.15
+++ openacs-4/packages/acs-authentication/tcl/authentication-procs.tcl	19 Jun 2017 18:35:00 -0000	1.89.2.16
@@ -214,7 +214,7 @@
             return [array get result]
         }
         set user_id [party::get_by_email -email $email]
-        if { $user_id eq "" } {
+        if { $user_id eq "" || ![acs_user::registered_user_p -user_id $user_id] } {            
             set result(auth_status) "no_account"
             set result(auth_message) [_ acs-subsite.Unknown_email]
             return [array get result]