Unable to load admin page

[FredBesterwitch]

Hi Im getting Unable to load admin page Exception

Magento.RestAPI version 1.0.4.0
Magento Enterprise ver. 1.14.2.2

The actual Admin url is https://www.mycompany.com/index.php/apples

Here is my code
IMagentoApi MagentoClient= new MagentoApi()
.SetCustomAdminUrlPart("apples")
.Initialize("https://www.mycompany.com", "XXXX.., "XXXX...")
.AuthenticateAdmin("XXX", "XXX");

Im getting an oauth token - see below
oauth_token=xbc8ab4ca48d7002cbcba4cb46533f75&oauth_token_secret=dec86400eac1aba2f27ccee0399787e2&oauth_callback_confirmed=true

but the next call -> https://www.mycompany.com/apples
When I checked fiddler, it's showing the login panel

Any Help appreciated

TIA