Requesting REST-GET gives me 403 but works fine in DHC I am stuck for hours now with a JSON REST problem:

I have a simple REST endpoint in my Drupal 8 App. If I call it with the DHC Chromium REST Extension like GET http://proreos/api/v1/checklawyer/1?_format=json, I get

127.0.0.1 - - [07/Jul/2016:15:03:54 +0200] "GET /api/v1/checklawyer/1?_format=json HTTP/1.1" 200 477 "-" "Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Ubuntu Chromium/51.0.2704.79 Chrome/51.0.2704.79 Safari/537.36"


That's wonderful. Also Drupal does all the requested processing.
But if I call it from curl like

curl 'http://proreos/api/v1/checklawyer/1?_format=json'

I get the bad 403 response:

127.0.0.1 - - [07/Jul/2016:15:10:27 +0200] "GET /api/v1/checklawyer/1?_format=json HTTP/1.1" 403 409 "-" "curl/7.35.0"


Well actually, I want to call it from a JS plugin like:

function checkLawyer() {
  var server = drupalSettings.bootasde.proreos_server;
  var id = drupalSettings.bootasde.asdeid;
  var jUrl = server+'api/v1/checklawyer/'+id+'?_format=json';
  console.log('Q: '+jUrl);
  jQuery.getJSON(jUrl);
}


It works fine, but unfortunately, it also gives me a 403 without any further Drupal backend processing:

127.0.0.1 - - [07/Jul/2016:15:06:03 +0200] "GET /api/v1/checklawyer/1?_format=json HTTP/1.1" 403 464 "http://proreos/asde/anwalt/1" "Mozilla/5.0 (X11; Ubuntu; Linux x86_64; rv:47.0) Gecko/20100101 Firefox/47.0"


Console says:

15:17:22.973 "Q: http://proreos/api/v1/checklawyer/1?_format=json"
XHR HTTP/1.1 403 Forbidden


Any idea would be great! Thanks.
Doomed, I am so stupid. Chrome had the admin cookie, FF had a simple user cookie. I forgot to permit the GET on the new endpoint in the user permissions!!!

So stupid. @Clive: Thanks a lot for your help and sorry for that waste of time.