Telegram Desktop App Not Working on Windows?

Preliminary Fixes.

Rule out internet issues: Make sure your device is connected to a stable internet connection by running other apps on the same computer. When other apps work fine, connectivity issues get ruled out. Check Telegram status: When the internet is connected correctly, the next step should be to check that Telegram isn't experiencing downtime. To do that, visit the downdetector website and type in "Telegram" to see what's happening. When Telegram's status is active and there are no reported issues on downdetector, Telegram's backend is unlikely to present any issues.Give Telegram a fresh start: After ruling out internet and backend issues, give Telegram a fresh start to remove the possibility of temporary glitches that prevent you from contacting your friends. Shut down the Telegram app completely, preferably from Task Manager, and then relaunch it.