Thanks Xuan,
the problem was the login module configuration. You have to configure the SAML2 Login Module into the ticket login module stack template, and assign /irj to that template.
If you need to perform the login without the SAML2 Login Module (maybe because IdP is not working Image may be NSFW.
Clik here to view.) access the portal with https://hostname/irj/portal?saml2=disabled
Image may be NSFW.
Clik here to view.