Hello, did you have the right login data?
Please check your data.
My own solution, i have reset the Adminstrator password:
Now you can login as “Administrator” with password “admin”, than you change the “user@example” password.
https://bitnami.com/stack/erpnext/virtual-machine
But the bitnami ERPNext VM based on Debian 9, Debian Stretch.
I`m search an better ERPNext - Linux Distribution combination:
Greetz
jannis