I belive the rachel needs to be all lowercase
Are you using one of the newer images from this post?
The admin login/password on these images is admin/Rachel+1. This is for the admin interface that is linked on the main page of RACHEL at http://10.10.10.10 .
The login.password for the system, should be “pi/rachel”. This is if you’re logging in on the command line or over SSH.
Hope this works for you. “pi/raspberry” is the default login/password for new installations of the raspberry pi operating system, but we generally change this for RACHEL.