More verbose error message

packages/server/src/api/routes/tests/oauth2.spec.ts

@@ -151,7 +151,9 @@ describe("/oauth2", () => {
         },
         {
           status: 400,
-          body: { message: "Name is not available." },
+          body: {
+            message: `OAuth2 config with name '${config2.name}' is already taken.`,
+          },
         }
       )
     })

packages/server/src/sdk/app/oauth2/crud.ts

@@ -65,7 +65,10 @@ export async function update(config: OAuth2Config): Promise<OAuth2Config> {
       c => c.name === config.name && c.id !== config.id
     )
   ) {
-    throw new HTTPError("Name is not available.", 400)
+    throw new HTTPError(
+      `OAuth2 config with name '${config.name}' is already taken.`,
+      400
+    )
   }
 
   doc.configs[config.id] = {