RedirectMaximum is an Integer property that specifies the maximum number of redirects that should be handled by the HTTP client. The default value for RedirectMaximum is Id_TIdHTTP_RedirectMax. 

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, the OnRedirect event handler is signalled 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.

TIdCustomHTTP.HandleRedirects 

TIdCustomHTTP.DoRequest 

EIdProtocolReplyError