If you enter a key intended for one activation method into the wrong environment, you will get an "invalid" error.
Microsoft has phased out the generic 120-day trial key for Exchange 2019. For permanent installations, you must use a genuine VL key or contact your Microsoft licensing partner. exchange 2019 product key invalid
Licensing changes do not take effect immediately. You must restart the service for the server to recognize the new license. Open services.msc . Locate Microsoft Exchange Information Store . Right-click and select Restart . 3. Verify via PowerShell or ECP If you enter a key intended for one