<!--@ DW_extranet_error_uk --> or
<!--@ DW_extranet_error_dk -->
If you do not like the text it provides, use an if defined to make your own:
<!--@ If Defined(DW_extranet_error_uk) -->
Your own login fail text or markup
<!--@ EndIf(DW_extranet_error_uk) -->
Available tags in login template:
http://templates.dynamicweb.dk/TemplateTags/Dynamicweb-template-tags/Module-tags/Extranet/Intranet/Login.aspx
Or <!--@ DwTemplateTags -->