Hi,
Could you try using a date range in your query by inserting the query "WHERE date DURING LAST_7_DAYS" after the FROM clause? Refer to the sample working query I used below.
Query: SELECT date, metrics.impressions FROM customer WHERE date DURING LAST_7_DAYS ORDER BY date LIMIT 10
If this still does not work, could you provide the screenshot of your error via reply privately to author so I could investigate this further?
Regards,
Dannison
AdWords API Team