The "passwd: pam_chauthtok(): conversation failure" error can occur when you try to change a user's password on a Linux or Unix system, and it usually indicates that there is a problem with the Pluggable Authentication Modules (PAM) configuration.
PAM is a system used by many Linux and Unix systems to authenticate users and manage user access to the system. When you try to change a user's password, the passwd command uses PAM to authenticate the user and verify that they are allowed to change their password.
The "pam_chauthtok(): conversation failure" error usually indicates that PAM is unable to complete the password change process due to a problem with the PAM configuration. This can be caused by a number of factors, including incorrect configuration settings, missing or invalid PAM modules, or problems with system libraries or dependencies.
To fix this error, you can try the following solutions:
Check the PAM configuration files for any mistakes or invalid settings. The PAM configuration files are usually located in the /etc/pam.d directory, and they have names that begin with "common-". You can use a text editor to open these files and check for any mistakes or invalid settings.
Make sure that all necessary PAM modules are installed and configured correctly. Some PAM modules are required for certain types of authentication or access control, and if these modules are missing or not configured correctly, it can cause the "pam_chauthtok(): conversation failure" error.
Check for any system library or dependency issues. The PAM system may depend on certain libraries or system dependencies, and if these are not installed or configured correctly, it can cause the "pam_chauthtok(): conversation failure" error.
Try using the passwd command with the -S option to see more information about the error. For example, you can use the following command:
passwd -S user
This will show you the status of the user's password, as well as any error messages or warning messages that may help you troubleshoot the problem.
If these solutions do not fix the "pam_chauthtok(): conversation failure" error, you may need to seek further assistance from your system administrator or a qualified IT professional.
For more information about PAM and how to troubleshoot PAM issues, you can consult the PAM documentation or use the man pam command to see the manual page.