Invalid Client Id

[albertomota]

Got an email with all the info required to use the REST API but can't get past the first step; whenever I try to access the URL below, even though I've double checked the client ID multiple times, keep getting a "Bullhorn OAuth Error - Invalid Client Id":

https://auth.bullhornstaffing.com/oauth ... _type=code

Help is greatly appreciated as we can't get past this first step..