SAML Integration with Zendesk

I configured keycloak with Zendesk using SAML but when the user press sign-in and directed to KEYCLOAK it shows Page Not Found

SAML SSO URL:https://keycloak-server:8443/auth/realms/newrealm/protocol/saml

I am not using localhost as Zendesk require https yet My url is showing me that certificate is expired
I don’t know if this is the problem or something else