at the minimum it would be important to show a useful message above the login form like Your session timed out due to inactivity for over 30min. Please login again. (or better)

reckon we don't need to alert people to keep the session active, or we could do this later.

Could say You may have been logged out due to inactivity. Please log in again.

As we can't know whether someone was last logged in 30 min ago, or 10 days ago .... and we can't know if user had checked remember me last etc.

I would suggest a message like this "Session expired, due to inactivity for more than 30 min. Please log in again".

We cannot know if the user was logged out due to inactivity for 30 min or not @KarthikRaja1388

@tsteur On what basis, do we expire the session may I ask?

It depends whether user clicked before "remember me" or not...

We could probably persist first whether user clicked "remember me or not"... but then we would also need to persist "expiration date" of session. This information is currently lost as soon as the user logs out. And we can't know whether user had last remember me active or when the user was last active. It starts even getting bit more complicated once you realise a user may be able to logged into multiple devices and we would need to store a new session cookie to detect a specific device etc. My comment is likely written bit confusing but it's just all a bit complicated.

If we could just show a more generic message we make a multi day job only a few minutes job.