Invalid scheme, expected connection string to start with "mongodb:" or "mongodb+srv://

Deploying my API then attempting to send a GET request to the DB results in Runtime.UnhandledPromiseRejection Invalid scheme, expected connection string to start with "mongodb:" or "mongodb+srv://

My db.js

import mongoose from "mongoose";
mongoose.Promise = global.Promise;
mongoose.set("strictQuery", false);

let connection_uri = process.env.MONGODB_URI;
let cachedMongoConn = null;

export const connectToDatabase = () => {
  return new Promise((resolve, reject) => {
    // mongoose.Promise = global.Promise;
    mongoose.connection
      .on("error", (error) => {
        console.log("Error: connection to DB failed");
        reject(error);
      })
      .on("close", () => {
        console.log("Error: Connection to DB lost");
        process.exit(1);
      })
      // Connected to DB
      .once("open", () => {
        // Display connection information
        const infos = mongoose.connections;

        infos.map((info) =>
          console.log(`Connected to ${info.host}:${info.port}/${info.name}`)
        );
        // Return successful promise
        resolve(cachedMongoConn);
      });
    if (!cachedMongoConn) {
      cachedMongoConn = mongoose.connect(connection_uri, {
        useNewUrlParser: true,
        useUnifiedTopology: true,
        connectTimeoutMS: 60000,
        bufferCommands: false, 
      });
    } else {
      console.log("MongoDB: using cached database instance");
      resolve(cachedMongoConn);
    }
  });
};

.env

MONGODB_URI=mongodb+srv://Username:Password:...

Everything "looks" correct and the connection string in the .env file is in the right format. So I'm not sure what the issue is.

Any help you can provide would be greatly appreciated.

I just had this same issue, removing the quotes before the URI link, solved it.

The problem is that the variable is most likely not formatted correctly.

Remove the spaces, the quotes, and the semi-colon at the end.

This

CONNECTION_URL =
"mongodb+srv://<UserName>:<Password>@cluster0.v5qzigz.mongodb.net/?retryWrites=true&w=majority";

Becomes this

CONNECTION_URL=mongodb+srv://<UserName>:<Password>@cluster0.v5qzigz.mongodb.net/?retryWrites=true&w=majority

credits to dev mikeym

Then the connection should work