Hello William1,
Please consider that the certificate received from the SSL provider has been included in a keystore in order to be used in LS Server.
Hence, it could be useful to inspect the contents of the keystore to see if anything is missing.
One way is the already suggested inspection via www.ssllabs.com, which shows how the keystore mounted on the Server is seen by a client.
If this way, as it seems to us, is not feasible for you, then another possibility is to inspect the keystore locally with keytool or openssl.
For instance, with
keytool -keystore <file> -list
you can check if there is at least one private key entry.
Regards
Dario