MongoDB and Express js connection problem (Bad auth code 8000)

Question

My port is 5000 MongoServerError: bad auth : Authentication failed. at Connection.onMessage (E:\React\Projects\assignment11\express\node_modules\mongodb\lib\cmap\connection.js:203:30) at MessageStream. (E:\React\Projects\assignment11\express\node_modules\mongodb\lib\cmap\connection.js:63:60) at MessageStream.emit (node:events:390:28) at processIncomingData (E:\React\Projects\assignment11\express\node_modules\mongodb\lib\cmap\message_stream.js:108:16) at MessageStream._write (E:\React\Projects\assignment11\express\node_modules\mongodb\lib\cmap\message_stream.js:28:9) at writeOrBuffer (node:internal/streams/writable:389:12) at _write (node:internal/streams/writable:330:10) at MessageStream.Writable.write (node:internal/streams/writable:334:10) at TLSSocket.ondata (node:internal/streams/readable:754:22) at TLSSocket.emit (node:events:390:28) { ok: 0, code: 8000, codeName: 'AtlasError', [Symbol(errorLabels)]: Set(0) {}

I tried so many times by changing the username password and also delete and recreate this. But Still, the problem occurs. I don't understand exactly why is this happening. Can anyone help me to tell the exact reason behind this?