i think you are missing a line like:
d-i user-setup/allow-password-weak boolean true ("ubuntu" isnt a very strong one) ....
the error message should indeed tell you instead of pointing to the root user ...
i think you are missing a line like:
d-i user-setup/ allow-password- weak boolean true
("ubuntu" isnt a very strong one) ....
the error message should indeed tell you instead of pointing to the root user ...