If you are offline (not connected to the internet) and you see the following dialog when your launch a CC 2019 app, follow the steps below to resolve this issue.
We are unable to verify your subscription status because, since you were last online and connected to Adobe servers, the local time on your system clock has changed unexpectedly. Assuming you have not intentionally altered the date and time on your machine, this condition typically occurs as a result of automatic time synchronization over an intermittent WiFi connection.
On your computer, use one of the following procedures (based on your operating system), to stop your system clock from syncing with the internet time and then launch your application while online.
You can turn on the syning of your computer clock the next time you are online.