Cannot migrate certificate to new server

[gnoul]

I migrate the zimbra server to another server follow this guide http://www.zimbra.com/forums/installation/16107-problem-moving-zcs-new-server-2.html.

When I start the zimbra on new server, it notice that Certificate expires. If i generate new self-certificate, the server work fine. I sure that old certificate is not expire. I do not know why i get this problem. Anyone can guide us the way to migrate certificate or move certificate to new server?

I appreciate for any help.

[ArcaneMagus]

I believe if the old certificate is close to expiring it generates a new certificate preemptively. Is the old certificate a commercial certificate?