Help with my .net code

We are in the process of migrating an application’s SSO integration. While the application currently works with our client’s SSO, we’re encountering an unexpected ‘temporarily available’ page when integrating with our SSO. We have transitioned the client-side SSO code from VB.NET to C#. Upon inspection, everything appears correct. The SAML response generated is consistent with what the client’s SSO receives. The issuer details are also identical. Despite these similarities, I’m uncertain why the integration isn’t functioning as expected.