Microsoft Outlook Web always disconnects, where is the “Stay connected” option?

A few days ago, I saw an option to “stay connected” when logging in on my workplace Office 365 account. I did not check it by mistake. Now, it’s gone and I randomly get disconnected during the day. Where is the option to stay connected?

I saw the same option before…

What I should see

But now it’s gone.

What I need to see