Hi La Baik Bae, I’m Eric, and I’d be happy to help!
The Microsoft Translator app for Windows 10 has been retired and is no longer available for download or updates, including offline language packs.  This change might be why you’re unable to connect to the server for downloading language packs on both Windows 10 and Android devices.
For continued translation support, consider using the Microsoft Translator web version or the Microsoft Translator app on Android, which still offer translation services. However, please note that offline language pack downloads may not be supported on all platforms. Alternatively, you might explore other translation apps that offer offline capabilities.
Let me know if you need further assistance!
Best,
Eric