Allow restricted user to change their own password

Question

Recently I have followed the articles below, however, the passwd file that I copied to a dir in the users `‘home`` dir.

However, when the new credentials are parsed into passwd, it ends up with the error of:

Authentication token manipulation error".

I have googled alot, however none of the solutions has worked.

https://access.redhat.com/solutions/65822

https://stackoverflow.com/questions/21498667/how-to-limit-user-commands-in-linux

Thanks!