The Active sessions card on /account lists every browser and device signed in to your account. Sign out any you don't recognise.
Read the list
The device you are using is at the top, labelled "This device" and marked "Active". Every other session shows the browser and operating system, such as "Chrome on macOS", with the IP address it signed in from. The card shows five sessions at first; click Show all N sessions to see the rest.
Sign out another session
Click Sign out session next to it. That device has to sign in again.
To sign out the device you are using, click Sign out at the bottom of the sidebar instead.
Changing your password does not end other sessions. If you changed it because someone else may know it, sign out the sessions you don't recognise here too.
In a client panel session
A session opened from the HostAfrica client panel lists only itself. Sign in directly to see and sign out your other sessions.