Okta Integration

So we integrated Okta and we are receiving the SAML Response from the custom page(SSO.aspx) that we created right after the authentication process . The problem is when we are redirecting to Admin/CMSAdministration.aspx page it keeps on redirecting to the Okta IdP URL. Any reason why?

// Authenticate and redirect
AuthenticationHelper.AuthenticateUser(user.UserName, true, true);
Response.Redirect("/Admin/CMSAdministration.aspx");