Access denied in Data scraping

I want to scrap data from an website, i have set MaxNoOfResults to 1000, but i am able to extract only max 300 results and browser is displaying issue “Access denied” at some point, after continuing some page. Browser is visiting all most all the pages but extracting only around 300 data.
i have set Properties:
DelayBetweenPagesMS to 10000
MaxNumberOfResults to 1000
i have used WriteCSV and IE browser for extracting data.

Can some one please suggest me how can i able to extract more data?