Not able to login after SAML2 setup with ATTASK (Workfront) using ADFS IDP

I am integrating Workfront(Attask) with my web application. I have configured SAML2 setting inside Attask setting tab and uploaded my Attask SP Metadata to IDP and IDP metadata to SP successfully. When I tried to test connection with given setting Saml token response was getting populated with ADFS attributes. However I selected checkbox for user-provisioning and mapped given attributes with Attask.

When I try to login using IDP url it was coming to attask login page with error. url error: login?arg0=mercatus2.attask-ondemand.com&ssoError=exception.sso.saml2.domainnotconfigured

login screen erorr

Let's try that again.
SAML configuration not present for mercatus2.attask-ondemand.com 

I am not sure whether this error is coming because my domain is not present for Workfront or is there any other reason??