Confirm that your internet connection works by opening a regular website.
Close the loader and try again after a short wait.
If you use a VPN or proxy, check whether it is interfering with the connection. Temporarily disconnect it only if your network permits.
Check whether Windows has a pending restart, then restart the computer if needed.
If the error continues, contact Synthera Support with the full message and mention whether you use a VPN, proxy, or restricted network.
Importante
Do not repeatedly retry license activation or disable your firewall as a general network fix.
Synthera Docs