with a wildcard cert from Equifax (think it is same as GeoTrust), and no CSR from the Zimbra server (it didnt' seem to be needed). I followed this:
Installing a GeoTrust Commercial Certificate - Zimbra :: Wiki
your "ca.pem" might be the same as the Equifax cert mentioned below, dunno, just telling you what I did. You could try renaming the ca.pem to commercial_ca.crt and see if they match in the first zmcertmgr command listed below. I also rename the files from what you have, to match the instructions... I think this process automatically looks for the private key in a file in that directory called "commercial.key".
- in the /opt/zimbra/ssl/zimbra/commercial directory....
- wget
https://www.geotrust.com/resources/r..._Authority.cer
- mv Equifax_Secure_Certificate_Authority.cer commercial_ca.crt
- mv cert.pem commercial.crt
- mv server.key commercial.key
- (as root) /opt/zimbra/bin/zmcertmgr verifycrt comm commercial.crt commercial_ca.crt
- if all reports as matching....
- (as root) /opt/zimbra/bin/zmcertmgr deploycrt commercial.crt commercial_ca.crt
good luck