diff --git a/src/api/viguno/client.spec.ts b/src/api/viguno/client.spec.ts
index 9f31bb5..378de5d 100644
--- a/src/api/viguno/client.spec.ts
+++ b/src/api/viguno/client.spec.ts
@@ -188,7 +188,8 @@ describe.concurrent('Viguno Client', () => {
 
   it('handles server error when resolving HPO term by ID', async () => {
     // arrange:
-    const errorMessage = 'Internal Server Error'
+    // const errorMessage = 'Internal Server Error'
+    const errorMessage = 'HPO term not found'
     fetchMocker.mockResponseOnce(JSON.stringify({ msg: errorMessage }), { status: 500 })
 
     // act:
diff --git a/src/api/viguno/client.ts b/src/api/viguno/client.ts
index 2418bc2..81a510a 100644
--- a/src/api/viguno/client.ts
+++ b/src/api/viguno/client.ts
@@ -96,8 +96,12 @@ export class VigunoClient {
     })
 
     if (!response.ok) {
-      const errorBody = await response.json()
-      throw new StatusCodeNotOk(errorBody.msg || response.statusText)
+      // TODO viguno does not responde with a json body on 500 so we don't have a message.
+      // TODO once this is fixed in viguno, we can use the code below.
+      // TODO https://github.com/varfish-org/viguno/issues/186
+      // const errorBody = await response.json()
+      // throw new StatusCodeNotOk(errorBody.msg || response.statusText)
+      throw new StatusCodeNotOk('HPO term not found')
     }
 
     try {