How do I access a PHP file hosted on a server?

How do I access a PHP file hosted on a server?

I have an android app which connects to a hosted db to fetch data.
When testing on localhost, it was working all fine.
I moved the db to a hosted server, a couple of days back and while trying
to run the app, it is throwing error while fetching data from db.
ERROR:
08-19 06:57:28.579: E/JSON Parser(32067): Error parsing data
org.json.JSONException: Value
'
The url being used by the app is: ipaddress/filename.php.
While reading the documentation provided by the web hosting company, I
remember reading something which said that 'the server treats the
index.html as the home page or default page for this directory'. Basically
when I type 'www.someaddress.com' or its IP, it returns index.html. I am
guessing that when the app pings the IP address provided in the url,
index.html file is being returned (is it even possible?).
The question is, how do I go around this problem? Has anyone encountered
the same issue?
Thanks in advance.