Keurig displaying 'Not ready'

Our office Keurig B60 is plugged in and turned on like it always is. There is sufficient water, and we cleaned the needle and cup. However, when we close the hatch, the screen still displays 'Not ready' with no other messages, and the lights do not blink.

This problem just started yesterday; we have not had any issues over the past 4-5 months. Any suggestions?