Unix PAM users are unable to log in to PaperCut NG/MF
This article refers to the User/Group sync source Unix Standard (PAM, nsswitch etc.).
Is your PAM (Pluggable Authentication Modules) setup configured to deny services by default?
Some Linux/Unix distributions adopt more stringent defaults for unspecified management groups i.e. account, authentication, password and session.
As with any security related modifications, make sure these authentication changes are right for you.
Try editing the /etc/pam.d/papercut PAM configuration file with appropriate permissions, and adding the following lines:
auth required pam_unix.so
account required pam_unix.so
Please note: The module name (pam_unix.so) may be different for your Linux/Unix distribution.
Save the file. Changes should come in to affect immediately.