The Mac computers store your network password information locally in what is called the "Keychain". When you change your network password, it is NOT automatically updated in the keychain which will cause an authentication problem when you try to print. Here is how to resolve this issue.
Keychain entry deletion
From the Mac desktop, select "Go" from the menu bar and then select "Utilities" from the drop down list.
On the Utilities screen, select "Keychain Access".
On the Keychain Access screen, find the printer you have installed on your computer. It will start with either "ADMINPRINT-" OR "STPRINT-" depending on the printer you have installed. Select the printer then press the delete key.
Once the printer entry has been deleted from the Keychain Access screen, close that window and go back to the printer queue and delete any print jobs that are pending or paused by clicking the "x" button next to the job(s).
Once any pending jobs have been deleted, reboot the computer. After reboot, try printing again to the printer and the authentication window will popup prompting for your network username and password. Enter your username and network password and ensure the “Remember this password in my keychain” checkbox is checked (otherwise you will have to enter your credentials every time you need to print).
As always, please contact Technology Services if you need additional assistance.