RedirectMaximum is a published Integer property in TIdHTTP, and specifies the maximum number of redirects that should be handled by the HTTP client. The default value for RedirectMaximum is 15. 

RedirectMaximum is provided to limit the effect of web-sites that perform numerous redirects, and to prevent stack overflow due to recursion. RedirectMaximum is used when HandleRedirects is True, otherwise it has no effect. 

RedirectMaximum is used with the internally maintained redirect count to determine when redirect handling is deferred to the application. When the redirect count exceeds the value of RedirectMaximum, DoRequest will signal the OnRedirect event handler to allow the application to respond to the redirect request. 

If the redirect is not handled by the application, an EIdProtocolReplyError exception will be raised.

TIdHTTP.HandleRedirects 

EIdProtocolReplyError