Chat is not reconnected
When the connection is lost for a considerable time, when reconnecting, a button can be pressed to reload the transmission but the chat keep frozen. The quick solution is to close the chat and open it after a few seconds, but it would be good if the reconnection is detected and the chat reconnects automatically as when the connection is lost for a few seconds.
With so many "welcome to the chat" that indicates you ve lost god knows how many messages without noticing you have been disconnected, either add a signal indicating if you re actually connected to the chat or not (a blue,red dot, maybe?) so users can reconnect, or create a routine that checks and reconnects users periodically.