docs: 📝 add port issue in FAQ

Author: yjaaidi

docs/instructions/faq.md

@@ -26,3 +26,28 @@ You can use `of` function to create a hardcoded observable.
 ```typescript
 stub.mockReturnValue(of(42));
 ```
+
+## `Error: listen EACCES: permission denied`
+
+When using Vitest Browser mode on some systems, you may encounter the following error:
+
+```
+Error: listen EACCES: permission denied 127.0.0.1:63315
+```
+
+In this case, you can override the port using the `--browser.api.port` or the configuration file:
+
+```ts
+export default defineConfig({
+  ...
+  test: {
+    ...
+    browser: {
+      ...
+      api: {
+        port: 63315,
+      },
+    },
+  },
+});
+```