Can not change user password in a shell.

[opn_mndr12101]

G'day members,

today I wanted to change my user password in a shell using passwd(5). I got
~~~
[user@OPNsense ~]$ passwd  -l
Changing local password for user
Old Password:
passwd: sorry
~~~
I'm pretty sure, the password is correct, because it works with sudo. What did I miss?