After checking the instance, and further discussions with @Anro, we found that the cause of the problem was existing users’ online/offline status not changing when switching a role from being online only to offline.
The user that @Anro was using to log in was created when the role they were assigned was online, and later the role was edited, however the user remained an online user.
I’ve created an issue to improve how the app behaves when roles are edited: Changing a role from being "online" to "offline" does not also change status of existing users having this role · Issue #8668 · medic/cht-core · GitHub