Problem: TIdHTTP in WebService

Hi, people.

I have a webservice (mywebsrv.dll) and I'm using an Indy component (TIdHTTP)
to change data by HTTPS.
When one people access the webservice, it works very well, but when more
than one people access (at same time) the webservice to change data using
TIdHTTP, I receive an error msg (Access Violation).

What's the problem? How can i fix it?

Thanks in advance,
Marco A. Meireles