Send XMPP error on unknown recipient

xmpp_tg/xmpp.py

@@ -153,6 +153,8 @@ class XMPPTelegram(ComponentXMPP):
             tg_peer = InputPeerChat(tg_id)
         elif iq['to'].bare.startswith( ('s', 'c') ):  # supergroup
             tg_peer = InputPeerChannel(tg_id, self.tg_dialogs[jid]['supergroups'][tg_id].access_hash)
+        else:
+            raise XMPPError(text="Invalid Telegram-ID")
             
         # peer OK. 
         if tg_peer: