C:\Program Files\Microsoft\Exchange Server\V15\Bin\LicenseDiag.cmd -Reset
Delete any accidental spaces at the beginning or end of the key if you copied and pasted it. 2. Common Technical Causes
The EAC can sometimes incorrectly report a valid key as invalid. Use the following command in the Exchange Management Shell: Microsoft Community Hub powershell exchange 2019 product key invalid
You have a valid Standard Edition product key, but you previously installed the Enterprise Edition (or vice versa). You cannot downgrade or cross-grade with a key. To switch editions, you must normally perform a recovery installation or uninstall/reinstall.
Get-ExchangeServer -Identity "YourServerName" | Format-List AdminDisplayVersion, IsExchangeTrialEdition Use code with caution. Use the following command in the Exchange Management
Set-ExchangeServer -Identity "YourServerName" -ProductKey "XXXXX-XXXXX-XXXXX-XXXXX-XXXXX" Use code with caution.
If the Exchange Management Console (EAC) or setup wizard rejects your product key, it is often due to one of the following reasons: exchange 2019 product key invalid
Do not copy and paste the key directly from your browser or a PDF into Exchange. Open a bare-text editor like . Paste the product key into the text file.