it means it's been that way for at least a month. What version of 6? You probably just had a tomcat or web server crash.
In the newer versions, it's in the system manager, so, from root at it's console --> service jboss restart.
Older versions have the license server in the web console (cdom). You can ssh to the hypervisor/dom0 and as root "xm stop udom" or xm reboot udom or something like that. Can't remember off hand, but there's 2 'domains' or virtual machines, 0 is the hypervisor, don't reboot that, reboot the one with id 1. I think 0=dom0 and 1=udom.
Anyway, if CM's webpage, in the top menu there's a spot for licensing to see which IP it's looking to for a license and you can figure out if it's smgr or cdom from there.
You might also need the certificaterenewalutility.bin version 2 or something from Avaya. If SMGR's certificates expired, that'd be a great reason it's web server died and can't serve up licenses.