https://knowledge.symantec.com/kb/index?page=content&id=SO8180&actp=search&viewlocale=en_US&searchid=1264523460902
If that document from another CA is still correct, it needs to “cat privkey.pem fullchain.pem >/somewhere/pound-cert.pem”.
cat privkey.pem fullchain.pem >/somewhere/pound-cert.pem