Either your Instagram has been permanently or temporarily banned for botting, or you forgot your Instagram password.
Try resetting your password. If you reset your password and you still cannot login, try waiting 24 hours to see if it was temporarily banned.
If all of those fail contact Instagram support.
This is very possible if you have downloaded a third-part app for Instagram, or if you have given someone your login details. If you account still exists (as you may have seen in option 1), you can try to change your password by sending a reset link to your email. Uninstall the third-party app, and don’t give out your password. If this doesn’t work, then email the Instagram help team.