License Renewal :

Just renew license.Had 25 days on license.Same license.Just go to Overview / Product Info / Licensing Information
Click on Change Lic. tab.Delete the current license showing, it' going to be the same.Copy & Paste in the license
field.Click Apply.You should get message " Your license key was successfully installed " Click OK.Close ZoneAlarm
and reboot.

Register to server & service expires in 389 days after reboot.

BTW
I renew from within ZoneAlarm using Support and Update Information / Renew tab

Hope this helps for renewal Registration issues.