I'm not sure what I am doing wrong

Please follow the below template, it will help us to help you!

Expected Behaviour:

Pi 3+ - login via SSH

Actual Behaviour:

ssh to ip address. Not sure of user name, but enter the password that works on the web admin interface. Can't determine what user name should be

Debug Token:

https://tricorder.pi-hole.net/m0ql97naux

The credentials to ssh into the Pi terminal are different than the Pi-hole web admin credentials.

For Raspbian OS (which you are running), the default user is pi and the login password is raspberry.

Thanks, jfb. Apparently, I didn't properly document the password change that I was prompted to change.

I just re-installed the OS image, and then pi-hole, from scratch.

Many thanks for the help.