For Jive data export service (analytics) the url to be used is different than jive REST apis.
The analytics service linked to your jive instance (adpworks.jiveon.com) might be either in US or EU.
For US the url is "api.jivesoftware.com" and one for EU is api-eu.jivesoftware.com.
So the above url will become https://api.jivesoftware.com/api/analytics/v1/export/activity?count=2&startIndex=2
You will have to check with jive support to know where your analytics service for your jive instance is.