diff --git a/frontend/src/network/tests/server-handlers.js b/frontend/src/network/tests/server-handlers.js
index c565d4cfb7..fdad0844f1 100644
--- a/frontend/src/network/tests/server-handlers.js
+++ b/frontend/src/network/tests/server-handlers.js
@@ -372,7 +372,7 @@ const faultyHandlers = [
     return res.once(
       ctx.status(403),
       ctx.json({
-        SubCode: `PrivateProject`,
+        error:{sub_code: `PRIVATE_PROJECT_NOT_ALLOWED`}
       }),
     );
   }),
diff --git a/frontend/src/utils/promise.js b/frontend/src/utils/promise.js
index a9af63507a..2ee009b416 100644
--- a/frontend/src/utils/promise.js
+++ b/frontend/src/utils/promise.js
@@ -24,7 +24,7 @@ export async function handleErrors(response) {
     .clone()
     .json()
     .then((res) => {
-      text = res.SubCode || response.statusText;
+      text = res.error?.sub_code || res.SubCode || response.statusText;
     });
   throw Error(text);
 }
diff --git a/frontend/src/views/project.js b/frontend/src/views/project.js
index 321bbd8826..ac80dd3fb8 100644
--- a/frontend/src/views/project.js
+++ b/frontend/src/views/project.js
@@ -198,7 +198,7 @@ export const ProjectDetailPage = () => {
       )}
       {error && (
         <>
-          {error.message === 'PrivateProject' ? (
+          {error.message === 'PRIVATE_PROJECT_NOT_ALLOWED' ? (
             <PrivateProjectError />
           ) : (
             <NotFound projectId={id} />