Ad Targeting - Find Entities by URNs API ClassCastException error message - linkedin

Question

I have some problem with the "Find Entities by URNs" API in order to retrieve the metadata and value information for a collection of URNs.
If I use the URL described in the doc (Sample request) with a valid access token:
https://api.linkedin.com/v2/adTargetingEntities?q=urns&urns=List(urn%3Ali%3AfieldOfStudy%3A100990,urn%3Ali%3Aorganization%3A1035,urn%3Ali%3Aseniority%3A9)&locale=(language:en,country:US)&oauth2_access_token=<a-valid-token>
I receive the message:
{
"serviceErrorCode": 0,
"message": "java.lang.ClassCastException",
"status": 500
}
Anyone have experience the same issue? Any idea how to fix it?
Also: how can i contact for technical support as in this case?
UPDATE:
I made some try and I fix using the following version:
https://api.linkedin.com/v2/adTargetingEntities?q=urns&urns=urn%3Ali%3AfieldOfStudy%3A100990&urns=urn%3Ali%3Aorganization%3A1035&urns=urn%3Ali%3Aseniority%3A9&locale.language=it&locale.country=IT&oauth2_access_token=<a-valid-token>
BUT the locale/language translation is not working. Could be this a working solutions?

Answer 1

From the support team:
Our docs are missing 1 critical piece of information. Whenever using
LIST and encoded URNs in the URL, we expect an additional header 'x-restli-protocol-version: 2.0.0'
The correct API call would be Request:
curl -X GET \
'https://api.linkedin.com/v2/adTargetingEntities?q=urns&urns=List(urn%3Ali%3Aindustry%3A1,urn%3Ali%3Aseniority%3A9)&locale=(language:it,country:IT)'
\
-H 'x-restli-protocol-version: 2.0.0' \
-H 'Authorization: Bearer <Token>'
Response:
{
"elements": [
{
"facetUrn": "urn:li:adTargetingFacet:industries",
"name": "Difesa e spazio",
"urn": "urn:li:industry:1"
},
{
"facetUrn": "urn:li:adTargetingFacet:seniorities",
"name": "Partner",
"urn": "urn:li:seniority:9"
}
],
"paging": {
"count": 2147483647,
"links": [],
"start": 0
}
}
Yes, it does provide a response in locale.
Hope this can help other guys in the future