code: async def on_raw_cap_nak(self, params):
          
          for capab in params[0].split():
              capab, _ = self._capability_normalize(capab)
              self._capabilities[capab] = False
              self._capabilities_requested.discard(capab)
  
          # If we have no capabilities left to process, end it.
          if not self._capabilities_requested and not self._capabilities_negotiating:
              await self.rawmsg('CAP', 'END')
docs: Update active capabilities: requested capability rejected.