3227217 - Error after configuring IAS as a proxy for Okta : Identity Provider could not process SAML2 authentication request sent over POST....

• After configuring IAS as a proxy for Okta (or other 3rd Party IdP) an error occurs when trying Service Provider (SP) Initiated logon to an application
• The Single Sign-on URL in the 3rd party IdP has the form of https://<Tenant ID>.accounts.ondemand.com/saml2/idp/sso/<Tenant ID>.accounts.ondemand.com
• The error message displayed is similar to: 

Identity Provider could not process SAML2 authentication request sent over POST due to SAML2 core error that prevents sending error response to the caller.
There is no SAML2 authentication request to validate in the given POST parameters Id

• Okta or other 3rd Party IdP
• Identity Authentication

Error, wrong, failed, fail, ACS, endpoint , KBA , BC-IAM-IDS , Identity Authentication Service , Problem