I have a system was was upgraded to vCenter 6.7 and esxi 6.5, only 6.5 due to hardware restrictions. This was all done three or four months ago and the system has been running well. I logged in today and it was all disconnected due to an expired license. Looks like somewhere along the way I forgot to attach the new licenses. I followed the process to switch the vCenter from the evaluation to the running license and that worked.
I switched the esxi the same and under assets and hosts is shows Is Licensed = yes and License Expiration = Never. When I switch back to look at my hosts, it says it is disconnected. If I log into the host directly, it says it has a license. But the vSphere client doesn't show the license operationally, but does show it when I try to assign it.
Am I missing a step here in assigning the license?
So verify what kind of you Lics you have. A few weeks ago i wasnt able to apply a Lic trough the Host client and only the way on the command line works(customer havent a vCenter because only one Host).