Hi Leonnor, here's help I found for you.

Fill the water reservoir halfway with vinegar. Add water: Fill the reservoir the rest of the way with water. Run the machine: Start the brew cycle without inserting a K-cup. Repeat until reservoir is empty, discarding the mug contents after each brewing cycle

Janice, mine won’t run without a K-cup in it. How do I trick it?

Here you go: https://www.thekitchn.com/how-to-clean-a-keurig-cooking-lessons-from-the-kitchn-218103

And: https://www.hometalk.com/35159623/how-to-clean-a-keurig

How to Clean a Keurig