Twitter api 1.1 403 forbidden early stage issue


Hi experts,
I tried to fetch post using below link:

it worked well as i tested 3 to 4 times… i fetched data with count 200.
and suddenly it started giving me 403 forbidden issue.I donot think I have crossed the limit because
it was 5 to 6th hit maximum.Then I tried new consumer token and ouath key but no use.
So what is the problem here and on same page I am not able to get descriptive error.
Tried to resolve issue through net surfing but all was not useful.Please help.

Thanks in Advance!