MaxAuthRetries is an Integer property that represents the maximum number of retries permitted when performing authentication for the TIdHTTP client connection. 

MaxAuthRetries is used when an HTTP protocol handler for the client connection attempts to process a protocol response code that indicates authentication or proxy authentication is required (401 or 407). 

MaxAuthRetries is compared to the current number of authentication requests issued in AuthRetries (or AuthProxyRetries) to determine if additional authentication requests are allowed. When permitted, the request is performed using the OnAuthorization event handler. 

The default value for MaxAuthRetries is Id_TIdHTTP_MaxAuthRetries as assigned during initialization of the component instance.

AuthRetries 

AuthProxyRetries 

OnAuthorization 

TIdHTTPProtocol