title: MongoParseError connecting to serverless Atlas DB
body: <p>I'm running a Node/Express/Mongoose App and when I try to connect it to a &quot;Serverless&quot; mongodb atlas database, I get the error</p>
  <p><code>MongoParseError: Text record must only set `authSource` or `replicaSet` at QueryReqWrap.callback (/home/XXX/node_modules/mongoose/node_modules/mongodb/lib/core/uri_parser.js:111:13)</code></p>
  <p>And in the code when I run a query against a &quot;User&quot; model, I get</p>
  <p><code>UnhandledPromiseRejectionWarning: Unhandled promise rejection. This error originated either by throwing inside of an async function without a catch block, or by rejecting a promise which was not handled with .catch(). To terminate the node process on unhandled promise rejection, use the CLI flag `--unhandled-rejections=strict` (see https://nodejs.org/api/cli.html#cli_unhandled_rejections_mode). (rejection id: 1) (node:32601) [DEP0018] DeprecationWarning: Unhandled promise rejections are deprecated. In the future, promise rejections that are not handled will terminate the Node.js process with a non-zero exit code.</code></p>
  <p>None of which show when I try a &quot;free&quot; regular version of the database (changing the connection URI obviously).</p>
  <p>I'm using mongoose 5.13.7 and mongodb 4.1.0. My connection string is &quot;mongodb+srv://user:password@serverlessinstance0.7eg4b.mongodb.net/db?retryWrites=true&amp;w=majority&amp;useMongoClient=true&quot;</p>
  <p>Any hints?</p>