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 -r1.114.2.29 -r1.114.2.30
--- openacs-4/packages/acs-authentication/tcl/authentication-procs.tcl	14 May 2023 11:09:44 -0000	1.114.2.29
+++ openacs-4/packages/acs-authentication/tcl/authentication-procs.tcl	15 Sep 2023 08:53:37 -0000	1.114.2.30
@@ -86,7 +86,9 @@
         set return_url [ad_get_login_url]
     }
 
-    ad_returnredirect -message $message -- $return_url
+    # If the login was issued from an external_registry,
+    # we have to allow the redirect to a complete url
+    ad_returnredirect -allow_complete_url=[expr {$external_registry ne ""}] -message $message -- $return_url
     ad_script_abort
 }