Next app deployment issue on vercel

In my next app, there is an api endpoint "posts" that return posts from the database. I used prisma and planetscale. When I deployed to vercel, api routes with no database querying are working but the one's with prisma code in it are not working (500 Internal Error). Note that I added env variables on vercel. So, I copied production branch env variable to local pc and ran "next build" and then "next start". The production build is working completely fine. It is not only working on vercel. Can anyone help me with this?