Using Moodle App is quite often that if you are using the chat activity, you are considered disconnected and it gives an error when you try to do something (write, check users online, ..)
It happened several times that I have been considered inactive, I didn't manage to reproduce it in the browser. Is it normal that it happens much more in the app than in the browser? Should there be a different setting for the app? Or should the app add certain seconds?
The message $string['notlogged'] = 'You are not logged in!' is shown when you have been inactive for a while. The message is really confusing, as actually you haven't logged out from the Moodle App just from the Chat. I'd change it for "You have been inactive in this chat for too long, please access this chat again. This configuration is set by your site administrators; if you don't know who they are please contact your teachers" (or something similar). If that string makes sense in Moodle LMS as it is (https://github.com/moodle/moodle/blob/master/mod/chat/lang/en/chat.php), maybe change it just for the app.
I saw another error that said "Error connecting to the server" I like the fact that it lets you reconnect without needing to go outside the chat and tap on it again. Maybe we could use the same idea with a different name, instead of "Reconnect" maybe a "Reconnect to this chat again"