This machine doesn't like oily, sticky beans. Most coffee beans purchased at a grocery store (even Starbucks or Peets - etc.) are roasted pretty dark with an oily sheen. Also most coffee beans from the store are very old - no matter how fresh they pretend to be. For example, at Safeway you will see a sign over the Peets coffee that says "roasted fresh, delivered daily" - that makes you think the beans are only a day or two old. But in reality they only remove the beans that are over 3 months old. The only way to get truely fresh roasted beans (unless you roast them yourself) is to find a roaster where you can buy beans that were roasted right there (many coffee shops pretend to be roasters but, in fact, they only buy more beans when they run out).
I have great luck buying beans directly from a roaster who will ship to me the same day they are roasted. RedBird Coffee has a delicious Espresso blend, the price is great and the beans are roasted just a little less dark so they are not oily and sticky. My Titanium works great with these beans. RedBird ships out the same day he roasts and you have your coffee about 2 days later. Very fresh.
In the meantime, you can lift the lid to the bean hopper and stir the beans with a popsicle stick or a chopstick and then they will grind for one or two coffees before you have to stir them again.
When choosing a coffee - don't buy Italian or French or Vienna roast - those dark roasts are oily and sticky. Ask for a Full City or Full City Plus roast - this is just slightly less dark than a Vienna Roast and shouldn't be oily looking. But freshness is still the key - any coffee beans that are several weeks past roasting day will start to become sticky and oily on the outside.
This is where I buy and I'll never go back to buying coffee at grocery store