MK.22410 (Customer) asked a question.
Salesforce Community SSO (not Portal)
The OKTA Salesforce guides all refer to Salesforce Portal. The newer release of Salesforce uses communities instead of Portal. When I try and setup SAML authentication with a Salesforce community using the OKTA Salesforce Portal Application, it does not work. The user login fails in Salesforce with the error "Failed: Invalid Portal Id".
Is there a different Application or instructions to setup Salesforce Community? Here is the difference between Salesforce communities and Customer portal
http://www.kineticgrowth.com/salesforce-communities-customer-partner-portals/
answering my own question. You basically have to do this
https://saml-doc.okta.com/Provisioning_Docs/Salesforce_Provisioning#addendum
Thank you for your answer. But I still have question, what should I entery in "custom domain" section.
It is like "**.cs60.force.com", what should I enter there?
you dont seem to have a custom domain, so leave it blank