Error is quite self explanatory:
Invalidoperationexception: an invalid request URI was provided. The request URI must either be an absolute URI or baseaddress must be set
"/api/Students"
is not a valid URI. Easiest test is to put in browser and see if you get back a valid response.
You are missing a url, something like:
https://mytestweb.com/api/students
The end point you are using must be hosted on some server for access. You are missing to add that server part to the end point. A complete valid end point.
Quote:
This instance represents a relative URI, and this property is valid only for absolute URIs.
Refer:
Uri.AbsoluteUri Property (System) | Microsoft Docs[
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