For some reason 200 seems to be a valid result for object creation as well as 202.

frontend/src/js/dialog/wb-new-project-dialog.js

@@ -38,7 +38,7 @@ class WBNewProjectDialog extends Component {
         makeArvadosRequest(arvHost, arvToken,
           '/arvados/v1/groups', { 'method': 'POST',
           'data': JSON.stringify(group),
-          'expectedStatus': 202 }
+          'expectedStatus': [200, 202] }
         ).then(callback);
       } }>
         <div>

frontend/src/js/misc/make-arvados-request.js

@@ -38,10 +38,15 @@ function makeArvadosRequest(arvHost, arvToken, endpoint, params={}) {
     xhr.onreadystatechange = () => {
       if (xhr.readyState !== 4)
         return;
-      if (xhr.status !== expectedStatus)
-        reject(xhr);
-      else
+
+      if ((expectedStatus instanceof Array) &&
+        expectedStatus.indexOf(xhr.status) !== -1) {
         accept(xhr);
+      } else if (expectedStatus === xhr.status) {
+        accept(xhr);
+      } else {
+        reject(xhr);
+      }
     };
     xhr.send(data);
   });