Hi. I am facing an issue when trying out the SP initiated flow (Salesforce being the SP). I do not get any option but "Login page" checkbox under Authentication service. I do not have an option to refersh the sandbox (probably coz the sandbox i am using is not licensed, it is the 30 day trial account). Not sure. Can anyone please help me how to proceed with this ? I need more options under Authnetication Service from which i can pick up my IDP instance to enable the SP initated flow.

Unable to map the subject to a Salesforce.com user AssertionId - Salesforce Stack Exchange0down votefavoriteI am new on salesforce, working on SAML2.0 using OKTA with salesforce. I have choose Salesforce(Federation ID)application on OKTA and follow the instruction given in OKTA, but failed to login in Salesforce using SAML2.0, It's come back as log out. I checked SAML Validator and find following

I cannot change the Authentication Service under My Domain Authentication Configuration after I did a refresh of my sandbox. After I did the sandbox refresh I configured the SSO settings and uploaded the IDP certificate provided from my IDP. I enabled SAML and try to get the authenticaton service to point to my SSO under the My DOmain - Authentication Configuration.
I am using SSO and am trying to have it so that if they go to my SFDC domain.

Expected Behavior:
When I go to https://my-domain.my.salesforce.com to be redirected to www.domain.com/sso to use my SSO credentials.

Actual Behavior:
When I go to https://my-domain.my.salesforce.com it stays on that page and I cannot use my SSO credentions. When I attempt to change the Authentication Service under Domain Management -> My Domain -> Authentication Configuration it always reverts back to Login Page

If I try to disable the SAML in the SInge Sign On Settings page is gives me the error message: Error: Your organization or community is currently using SAML as an authentication method, so you can’t disable it.
So my problem is that I can not disable SAML or I can active the use of SSO authenication. 

I am confident the SSO settings are correct as they are the same as before the Sandbox refreshed where it worked just fine.
The Authentication Service under Domain Management -> My Domain -> Authentication Configuration always reverts back to Login Page seems to be the key issue her.

Please help