It's a memory hungry operation, be sure to have enough heap space available to zmjava. If not, bring it from 256 to 1024.
~$ zmlocalconfig zimbra_zmjava_options
zimbra_zmjava_options = -Xmx256m -Dhttps.protocols=TLSv1,TLSv1.1,TLSv1.2 -Djdk.tls.client.protocols=TLSv1,TLSv1.1,TLSv1.2 -Djava.net.preferIPv4Stack=true