Sometimes we install Windows Server 2016/2019 only using a trial license. This trial license only runs for 180 days. After that it will expire.
the picture above shows that the windows server has expired license. What happens if the Windows License Trial expires? Server machine will shutdown itself within 1 hour.
For example, You can look at corner down right, it will show the windows countdown will expire.
Or start CMD and run slmgr.
slmgr -dlv
Pay attention to the Time based activation expiration and theremaining Windows rearm count. When the period comes to an end, run slmgr -rearm to extend it by another 180 days.
When the period reach to an end, run slmgr -rearm to extend 180 days.
slmgr -rearm
We need restart server for effect.
And then up again, we will se result 180 days again. Ypu can run slmgr -dli.
slmgr -dli 
