Not able to Access certain DOORS Next http resource links which are being provided in API response itself.

I fetched the metadata for a particular Artifact using oslc API calls, and I'm getting URLs in rdf:resource in the response.xml. When I'm trying to do a GET request on the URL, I'm ending up with HTTP 400 : Bad Request.
Samples attached below:-
http://dng_instance_url/attribute-data-type/Status_CRS_Type/new-changed
http://dng_instance_url/attribute-data-type/Safety_Type/ASIL-D-D
Accepted answer

I imagine/guess these are RDF URIs so they typically aren't real URLs - they're intended to be unique identifiers so that, for example, the same URI identifies the "same" thing in two different projects/components. You'll see these values in the Manage Component Properties as the "URI" on Artifact Type/Artifact Attribute/Attribute Data type entries.
The DOORS Next resource type URL for e.g. an Artifact type is unique in the RM server but it's common to want to have a way of referring to two things in a server which are logically the same, which the resource type URL can't do, so URIs provide a way to relate types in different components/projects/servers as being the same thing.