some progress

node_modules/mongoose/lib/error/serverSelection.js

@@ -0,0 +1,61 @@
+/*!
+ * Module dependencies.
+ */
+
+'use strict';
+
+const MongooseError = require('./mongooseError');
+const allServersUnknown = require('../helpers/topology/allServersUnknown');
+const isAtlas = require('../helpers/topology/isAtlas');
+const isSSLError = require('../helpers/topology/isSSLError');
+
+/*!
+ * ignore
+ */
+
+const atlasMessage = 'Could not connect to any servers in your MongoDB Atlas cluster. ' +
+  'One common reason is that you\'re trying to access the database from ' +
+  'an IP that isn\'t whitelisted. Make sure your current IP address is on your Atlas ' +
+  'cluster\'s IP whitelist: https://www.mongodb.com/docs/atlas/security-whitelist/';
+
+const sslMessage = 'Mongoose is connecting with SSL enabled, but the server is ' +
+  'not accepting SSL connections. Please ensure that the MongoDB server you are ' +
+  'connecting to is configured to accept SSL connections. Learn more: ' +
+  'https://mongoosejs.com/docs/tutorials/ssl.html';
+
+class MongooseServerSelectionError extends MongooseError {
+  /**
+   * MongooseServerSelectionError constructor
+   *
+   * @api private
+   */
+  assimilateError(err) {
+    const reason = err.reason;
+    // Special message for a case that is likely due to IP whitelisting issues.
+    const isAtlasWhitelistError = isAtlas(reason) &&
+      allServersUnknown(reason) &&
+      err.message.indexOf('bad auth') === -1 &&
+      err.message.indexOf('Authentication failed') === -1;
+
+    if (isAtlasWhitelistError) {
+      this.message = atlasMessage;
+    } else if (isSSLError(reason)) {
+      this.message = sslMessage;
+    } else {
+      this.message = err.message;
+    }
+    for (const key in err) {
+      if (key !== 'name') {
+        this[key] = err[key];
+      }
+    }
+
+    return this;
+  }
+}
+
+Object.defineProperty(MongooseServerSelectionError.prototype, 'name', {
+  value: 'MongooseServerSelectionError'
+});
+
+module.exports = MongooseServerSelectionError;