Cause of error code 306

See below

Solution for error code 306

Refers to occasions when you're looking to print from a Mac. A solution for this issue is to: Click the Apple icon in the top left of the screen. Click System Preferences. Click Print & Fax. If the padlock in the bottom left is locked: Click it, enter your password and click OK. Click the – button. to remove the printer and the + to add it again leaving the options on default.