web.xml welcome-file redirection returns HTTP 403

WE get HTTP 403 forbidden when there is redirection to web.xml welcome-file.
Example:

• Application name Portal

web.xml
<welcome-file-list>
<welcome-file>portal.do</welcome-file>
</welcome-file-list>

What should happen is when calling http://ip:port/Portal the web server will give back the http://ip:port/Portal/portal.do

What we get when calling http://ip:port/Portal is HTTP 403

Calling directly to http://ip:port/Portal/portal.do works fine.

It is very similar to issue https://issues.jboss.org/browse/WFLY-3279

Thanks,
Roi Mizrachi