Why is my keurig duo only making cups and not a pot?

When I press the pot option to make 12 cups in the pot. The lights start flashing and then water will come out the other side into the single cup maker. It will flow for a minute or two then it’ll switch over to the pot and brew maybe 1 cup of coffee into the pot and then stop. When it does the pot light goes from green to red. And no longer pumps water to either side. I just want to make a 12 cup pot of coffee lol