[▲ Vercel Community](/) · [Categories](/categories) · [Latest](/latest) · [Top](/top) · [Live](/live) [v0](/c/v0/59) # Next.js preview deployment error: Cannot read properties of undefined (reading 'call') 26 views · 3 likes · 3 posts Bilalalam58 7827 (@bilalalam58-7827) · 2026-03-16 · ♥ 1  Hello Vercel Support Team, I am encountering a sudden application error when opening the **Preview deployment** of my project. The preview environment loads an error page instead of the app. ## Error Message > **An application error has occurred while loading `/auth/login`** > **TypeError: Cannot read properties of undefined (reading 'call')** The stack trace references a `Next.js` runtime error inside the compiled preview build (`webpack` / `Next.js` runtime). This error appeared unexpectedly — the preview was working earlier and no major structural changes were made immediately before this started occurring. ## Observed Behavior - The preview deployment opens but immediately throws the runtime error. - The app does not render and the `/auth/login` route fails. - This only appears in the **Preview environment**. - The error originates during module initialization (`options.factory` / `__webpack_require__`). ## What I Would Like Help Verifying 1. Whether the preview build environment may have corrupted cache or dependency resolution. 2. If the preview deployment runtime has any known issue related to `Next.js` module loading. 3. Whether clearing the build cache or re-deploying the preview would resolve this. If necessary, I can also provide: - Deployment URL - Commit hash - Project ID - Build logs Please let me know what additional details would help diagnose this issue. Thank you. MarnixB (@marnix-3108) · 2026-03-16 · ♥ 1 Hi! Maybe our tickets are connected to eachother. It seems that next is being really weird within the sandbox/preview since today; https://community.vercel.com/t/v0-preview-fails-with-sh-line-1-next-command-not-found-error-in-sandbox/36324/7 Pauline P. Narvas (@pawlean) · 2026-03-20 · ♥ 1 Let us know if you still see this!