Pasting not possible

If you cannot copy/paste text into Telegram, check if you are using Webroot. Add Telegram Desktop to the whitelist of that software. May be possible that you have to repeat it after each Telegram Desktop update.

  • Webroot Settings
  • Identify Protection
  • Application Control
  • Add Application or select Telegram Desktop from the unsorted list and Allow it

Quick alternative: Webroot Settings → Disable Identity Shield.

Link: Some alternative malware scanners for Windows