Can't deploy frontend on vercel.

[tawanchaiii]

I have deployed backend on heroku. (used cloudinary to stored images)
And I tried yarn next dev and yarn next build on local.
(I have added NEXT_PUBLIC_STRAPI_API_URL from heroku to .env)

It's working on local.

When I pushed the repo to and tried to deploy on vercel.
(I have added NEXT_PUBLIC_STRAPI_API_URL to Environment Variables.)

So I tried to deploy fronted on heroku.

It's still not working (categories.map or articles.map is not a function.).