Hi When you set up the chat service which online service do you have an account with? WhatsApp, or Zoom, for example, or some other virtual meeting or group app? There are so many out there, or maybe it is an internal/corporate chat! By the way - be sure that your service still is using XMPP protocol. For example, I read somewhere that Facebook Message service stopped using it in 2015. You'll need the proper server name to connect to when you set up Thunderbird to connect to that specific chat service. Usually you can find that on the service support pages. You also need to enter the same password you used to sign up for the online chat account in Thunderbird, so that Thunderbird can connect to your account. If the passwords don't match or the server is not the right one, Thunderbird can't connect you. Hope that helps. More info here https://support.mozilla.org/en-US/kb/instant-messaging-and-chat Or were you wanting to chat with Thunderbird support? There's info here https://www.thunderbird.net/en-US/contact/ and https://wiki.mozilla.org/Matrix