The surveys look for specific people in terms of age, gender and so on. If your answers show you do not match that target audience, the survey will end. The best way to qualify to more high-payout surveys is to complete (and keep up-to-date) your Survey Profile (available here: https://drumo.com/me/profile
Remember to always provide consistent and honest answers - surveys are made in such a way to easily spot fake, inconsistent answers and fake data (that's why some may ask the same or similar questions multiple times).
On the contrary, one of the ways to have more surveys "fitting" your profile (and therefore complete more surveys) is to answer as honestly as possible.
We know it's frustrating to spend some time on a survey and then get suddenly disqualified, but do not worry: different surveys are looking for different people and demographics, and our team is working the whole time to increase our survey inventory to offer you more surveys to complete.