Account logged me out

My account logged me out and I missed an assignment. What is the reason it does this? I used the email I registered with continually and it kept saying “user not found.” What is the reason for this?

I responded to your other message, but just so you are aware, our system does log users out after long periods of inactivity. Just log back in with your chosen username, not your email. Your username is: ameliadavis
Feel free to email if you need further support help!