Tips and Tricks - Authentication issue when printing on Mac after a password change
You will want to clear the keychains after password change
You or the user can click on Go on the main file menu at the top of the screen.
Then click on Go to Folder
Enter in ~/Library/Keychains then click on Go.
Select the list view icon marked in red above.
Select the login keychain
Move the item to the trash. You can log out and log into the computer.
Select something to print
You will enter your user name and password then you can select "Remember this password in my keychain". If you do not select this option
you will enter your username and password each time you try to print something.