When activating Dashboard Server you see the following message:
"This key has expired"
Some licence activation keys (such as for technical preview releases and evaluation licences) are only valid for a limited time period. Contact SquaredUp Support to obtain an up-to-date activation key.
For other renewable licences you will normally be able to renew your licence before it expires. As part of this renewal process, Dashboard Server will update your existing licence with the new subscription term, so you can simply reactivate your licence for the changes to take effect.
If your licence expires before you are able to renew then you may be sent a new licence activation key, which you should paste into the activation screen to activate the new key, when prompted when you open Dashboard Server.