I created a web application using Nextjs and deployed it using vercel. In my local host, I am able to interact with it like normal (buttons function) and the contents adjust according to the screen size but the deployed site does not look or function that way. It has the following errors:

• Database Error: VercelPostgresError: VercelPostgresError – ‘missing_connection_string’: You did not supply a ‘connectionString’ and no ‘POSTGRES_URL’ env var was found.
• Uncaught Error: Minified React error #329; visit https://reactjs.org/docs/error-decoder.html?invariant=329 for the full message or use the non-minified dev environment for full errors and additional helpful warnings.

I tried redeploying and even creating/saving environment variables (by going to the project settings in the vercel website and adding it in) but I saw that it was overridden by the project and that there were already variables in place.