# Deployment fail

**URL:** <https://community.prismic.io/t/deployment-fail/8615>\
**Category:** Developing with Prismic\
**Tags:** nextjs\
**Created:** [January 11, 2022, 3:07pm UTC](https://community.prismic.io/t/deployment-fail/8615 "2022-01-11T15:07:18Z")\
**Posts on this page:** 2\
**Page:** 1

<div class="post-metadata">

**Author:** ![jsprunet](https://avatars.discourse-cdn.com/v4/letter/j/9dc877/32.png) [@jsprunet](https://community.prismic.io/u/jsprunet)\
**Post date:** [January 11, 2022, 3:07pm UTC](https://community.prismic.io/t/deployment-fail/8615/1 "2022-01-11T15:07:19Z")

</div>

Hello,

We are using Prismic with Vercel and Next.js for a multi-language content and ecommerce website.  
After creating dozens of pages, custom types, slices... we are facing an issue on one or our new content.

We created a new custom type, only using Prismic on-shelf items (no change in jason queries).  
This custom type is used to create a content bloc and populated with actual content, then used in a "Static Slice" in a page.

After publishing this page with this specific slice x custom type, when we deploy, we endlessly have deployment error. Please see the error log below.

Could you help us ? Does this case or log rings a bell for anyone ?

Thanks in advance !

JS

```auto
Unhandled error during request: TypeError: Cannot read property '0' of undefined
    at /vercel/path0/.next/serverless/pages/[lang]/[page].js:11185:35
    at runMicrotasks (<anonymous>)
    at processTicksAndRejections (internal/process/task_queues.js:97:5)
    at async Promise.all (index 0)
    at async staticSliceResolver (/vercel/path0/.next/serverless/pages/[lang]/[page].js:11182:10)
    at async getByUID (/vercel/path0/.next/serverless/pages/[lang]/[page].js:11220:20)
    at async getStaticProps (/vercel/path0/.next/serverless/pages/[lang]/[page].js:5045:33)
    at async renderToHTML (/vercel/path0/node_modules/next/dist/next-server/server/render.js:26:109)
    at async renderReqToHTML (/vercel/path0/.next/serverless/pages/[lang]/[page].js:24640:22)
    at async Object.exportPage [as default] (/vercel/path0/node_modules/next/dist/export/worker.js:12:92)
Error occurred prerendering page "/fr-fr/angell-test1". Read more: https://err.sh/next.js/prerender-error
TypeError: Cannot read property '0' of undefined
    at /vercel/path0/.next/serverless/pages/[lang]/[page].js:11185:35
    at runMicrotasks (<anonymous>)
    at processTicksAndRejections (internal/process/task_queues.js:97:5)
    at async Promise.all (index 0)
    at async staticSliceResolver (/vercel/path0/.next/serverless/pages/[lang]/[page].js:11182:10)
    at async getByUID (/vercel/path0/.next/serverless/pages/[lang]/[page].js:11220:20)
    at async getStaticProps (/vercel/path0/.next/serverless/pages/[lang]/[page].js:5045:33)
    at async renderToHTML (/vercel/path0/node_modules/next/dist/next-server/server/render.js:26:109)
    at async renderReqToHTML (/vercel/path0/.next/serverless/pages/[lang]/[page].js:24640:22)
    at async Object.exportPage [as default] (/vercel/path0/node_modules/next/dist/export/worker.js:12:92)

```

---

<div class="post-metadata">

**Author:** ![Pau](https://dub1.discourse-cdn.com/flex013/user_avatar/community.prismic.io/pau/32/5422_2.png) [@Pau](https://community.prismic.io/u/Pau)\
**Post date:** [January 11, 2022, 9:21pm UTC](https://community.prismic.io/t/deployment-fail/8615/2 "2022-01-11T21:21:58Z")

</div>

Hello @jsprunet. Thanks for reaching out.

This: `Cannot read property '0' of undefined` seems to be a JavaScript-related error. Can you check if you're correctly verifying the values of your array methods?

[Here's a related thread I found online](https://stackoverflow.com/questions/18947556/typeerror-cannot-read-property-0-from-undefined)