You received the license key from ShortPoint and tried to activate the license key on ShortPoint License manager in SharePoint Central Administration. Then you got this error:
ShortPoint License activation failed:
ActivationFailed: The underlying connection was closed. Could not establish trust relationship for the SSL/TLS secure channel.
Remote connection to the server was not established because activation.shortpoint.com URL it was blocked by your firewall.
You can ask the IT team to whitelist activation.shortpoint.com.
1. On the licensing page, click the Offline Activation button:
2. Copy the farm code from the pop-up window (shown with an arrow below).
3. Send the farm code and the license key you are trying to activate with to email@example.com, and we will activate the license on your behalf.