There are multiple ways to get the validity of the certificate installed on the server .
1.If we have access to server login and open the keystore and verify using keytool
keytool -details -alias mycert -keystore abc.jks -password **** -v
2.use one of the client to browse the URL using https://ip:port:/ that will present the certificate in the browser after successful connection .
3.Use openssl to get the certificate and verify the validity .
openssl s_client -connect ip:port 2>/dev/null |openssl x509 -noout -dates