Cannot Create Session

Somewhere in your code is outputing to the view before you create the session.

Check your code for output to the screen ( view ).

It means that the headers have already been sent before you used the session.

Start at your BaseController and work upwards to your other Controllers.

Place an ( exit(); ) in your code to check for the output to the view.

Thanks. I had a <<?php in one of my app/Config/Boot files.

Simpler is always better