Unable to get issuer certificate
If you are getting this error as you deploy the certificate:
XXXXX ERROR: Invalid Certificate:....error 20 at 0 depth lookup:unable to get local issuer certificate XXXXX ERROR: provided cert isn't valid.
or this error,
this alternate error error 2 at 1 depth lookup
it means the certificate path or chain is broken and you are missing certificate files. In most cases the intermediate cert is the path or chain that is affected.
For more info on certificate path verification, please take a look at http://www.herongyang.com/crypto/openssl_verify.html.
For more zimbra specific details and discussion see http://www.zimbra.com/forums/administrators/43361-thawte-ssl123-did-not-use-admin-panel.html