Issue in Single Logout from Azure with Rails(Idp initiated Logout)

Question

We are using Single sign-on with Rails application, For configuration process, we are using the Fingerprint of the Certificate(Base64) and other required attributes.

Single sign-on is working fine as expected, while using single logout through Logout Url,
we are facing issue in verifying the certificate in background process, the condition is returning as false while checking whether it is a valid certificate, we are using trial account now.

Can you please explain the process in it, how the certificate is verified and what are the configurations we needed in Single sign-on and Single Logout.