My Discourse community is based on a recent migration from phpBB. There are over 1000 user accounts.
This is a self-hosted docker standard installation.
I recently wanted to send a chat message to a member but was prevented because of this chat disabled message (for the green circle).
Only some of the user accounts (but a significant number) have chat disabled. Perhaps this state was set in phpBB and migrated.
Without having made any change. when I look at the preference for an account of interest, I see that chat is marked as enabled.
If I cycle the state between disabled/save/enable/save, there is no difference in the behaviour - I am still unable to communicate by chat.