in my case i needed to change .env.local to .env 

you also need to do `npm i dotenv' and ` import 'dotenv/config' `

//i have this error because i changed of folder .env file to fix it i do....

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import dotenv from 'dotenv';

dotenv.config({ path: 'path/to/.env' });

this accured to me cause of the .env file being in the worng dirctory