diff --git a/src/Umbraco.Web.UI.Client/src/mocks/domains/install.handlers.ts b/src/Umbraco.Web.UI.Client/src/mocks/domains/install.handlers.ts
index ba6d6fce72..103b2261f2 100644
--- a/src/Umbraco.Web.UI.Client/src/mocks/domains/install.handlers.ts
+++ b/src/Umbraco.Web.UI.Client/src/mocks/domains/install.handlers.ts
@@ -73,16 +73,18 @@ export const handlers = [
 		);
 	}),
 
-	rest.post<PostInstallRequest>(umbracoPath('/install/setup'), async (req, res, ctx) => {
+	rest.post(umbracoPath('/install/setup'), async (req, res, ctx) => {
 		await new Promise((resolve) => setTimeout(resolve, (Math.random() + 1) * 1000)); // simulate a delay of 1-2 seconds
+		const body = await req.json<PostInstallRequest>();
 
-		if (req.body.database?.name === 'fail') {
+		if (body.database?.name === 'fail') {
 			return res(
 				// Respond with a 200 status code
 				ctx.status(400),
 				ctx.json<ProblemDetails>({
 					type: 'validation',
 					status: 400,
+					detail: 'Something went wrong',
 					errors: {
 						name: ['Database name is invalid'],
 					},