Assuming your list criteria are valid, It might be that the list is timing out before it finishes.
When I've had problems running a smart list, I've found that I can often create a Static List coupled with a Smart Campagin to gather leads using the same critera..
1. Create a List.
2. Create a Smart Camapign
a Smart List--same criteria
b. Flow: Add to list name created in step 1
c. Scheudle: Run once/Run Now.
It will probably take a while, but you should have less probem opening the static list than generating a smart list.