خطأ عند الإتصال بقواعد البيانات mongo db

السلام عليكم.

الرجاء توضيح الخطأ التالي.

CastError: Cast to ObjectId failed for value "undefined" (type string) at path "_id" for model "User"
    at ObjectId.cast (C:\Users\saadaoui\Desktop\chat-app\server\node_modules\mongoose\lib\schema\objectid.js:250:11)       
    at SchemaType.applySetters (C:\Users\saadaoui\Desktop\chat-app\server\node_modules\mongoose\lib\schematype.js:1220:12) 
    at SchemaType.castForQuery (C:\Users\saadaoui\Desktop\chat-app\server\node_modules\mongoose\lib\schematype.js:1632:15) 
    at ObjectId.handleSingle (C:\Users\saadaoui\Desktop\chat-app\server\node_modules\mongoose\lib\schematype.js:1562:15)   
    at SchemaType.castForQuery (C:\Users\saadaoui\Desktop\chat-app\server\node_modules\mongoose\lib\schematype.js:1629:20) 
    at cast (C:\Users\saadaoui\Desktop\chat-app\server\node_modules\mongoose\lib\cast.js:334:39)
    at Query.cast (C:\Users\saadaoui\Desktop\chat-app\server\node_modules\mongoose\lib\query.js:4911:12)
    at Query._castConditions (C:\Users\saadaoui\Desktop\chat-app\server\node_modules\mongoose\lib\query.js:2232:10)        
    at model.Query._find (C:\Users\saadaoui\Desktop\chat-app\server\node_modules\mongoose\lib\query.js:2258:8)
    at model.Query.exec (C:\Users\saadaoui\Desktop\chat-app\server\node_modules\mongoose\lib\query.js:4430:28) {
  stringValue: '"undefined"',
  messageFormat: undefined,
  kind: 'ObjectId',
  value: 'undefined',
  path: '_id',
  reason: BSONError: Argument passed in must be a string of 12 bytes or a string of 24 hex characters or an integer        
      at new ObjectId (C:\Users\saadaoui\Desktop\chat-app\server\node_modules\bson\lib\bson.cjs:2055:23)
      at castObjectId (C:\Users\saadaoui\Desktop\chat-app\server\node_modules\mongoose\lib\cast\objectid.js:25:12)
      at ObjectId.cast (C:\Users\saadaoui\Desktop\chat-app\server\node_modules\mongoose\lib\schema\objectid.js:248:12)     
      at SchemaType.applySetters (C:\Users\saadaoui\Desktop\chat-app\server\node_modules\mongoose\lib\schematype.js:1220:12)
      at SchemaType.castForQuery (C:\Users\saadaoui\Desktop\chat-app\server\node_modules\mongoose\lib\schematype.js:1632:15)
      at ObjectId.handleSingle (C:\Users\saadaoui\Desktop\chat-app\server\node_modules\mongoose\lib\schematype.js:1562:15) 
      at SchemaType.castForQuery (C:\Users\saadaoui\Desktop\chat-app\server\node_modules\mongoose\lib\schematype.js:1629:20)
      at cast (C:\Users\saadaoui\Desktop\chat-app\server\node_modules\mongoose\lib\cast.js:334:39)
      at Query.cast (C:\Users\saadaoui\Desktop\chat-app\server\node_modules\mongoose\lib\query.js:4911:12)
      at Query._castConditions (C:\Users\saadaoui\Desktop\chat-app\server\node_modules\mongoose\lib\query.js:2232:10),     
  valueType: 'string',
  model: Model { User }
}
CastError: Cast to ObjectId failed for value "undefined" (type string) at path "_id" for model "User"
    at ObjectId.cast (C:\Users\saadaoui\Desktop\chat-app\server\node_modules\mongoose\lib\schema\objectid.js:250:11)       
    at SchemaType.applySetters (C:\Users\saadaoui\Desktop\chat-app\server\node_modules\mongoose\lib\schematype.js:1220:12) 
    at SchemaType.castForQuery (C:\Users\saadaoui\Desktop\chat-app\server\node_modules\mongoose\lib\schematype.js:1632:15) 
    at ObjectId.handleSingle (C:\Users\saadaoui\Desktop\chat-app\server\node_modules\mongoose\lib\schematype.js:1562:15)   
    at SchemaType.castForQuery (C:\Users\saadaoui\Desktop\chat-app\server\node_modules\mongoose\lib\schematype.js:1629:20) 
    at cast (C:\Users\saadaoui\Desktop\chat-app\server\node_modules\mongoose\lib\cast.js:334:39)
    at Query.cast (C:\Users\saadaoui\Desktop\chat-app\server\node_modules\mongoose\lib\query.js:4911:12)
    at Query._castConditions (C:\Users\saadaoui\Desktop\chat-app\server\node_modules\mongoose\lib\query.js:2232:10)        
    at model.Query._find (C:\Users\saadaoui\Desktop\chat-app\server\node_modules\mongoose\lib\query.js:2258:8)
    at model.Query.exec (C:\Users\saadaoui\Desktop\chat-app\server\node_modules\mongoose\lib\query.js:4430:28) {
  stringValue: '"undefined"',
  messageFormat: undefined,
  kind: 'ObjectId',
  value: 'undefined',
  path: '_id',
  reason: BSONError: Argument passed in must be a string of 12 bytes or a string of 24 hex characters or an integer        
      at new ObjectId (C:\Users\saadaoui\Desktop\chat-app\server\node_modules\bson\lib\bson.cjs:2055:23)
      at castObjectId (C:\Users\saadaoui\Desktop\chat-app\server\node_modules\mongoose\lib\cast\objectid.js:25:12)
      at ObjectId.cast (C:\Users\saadaoui\Desktop\chat-app\server\node_modules\mongoose\lib\schema\objectid.js:248:12)     
      at SchemaType.applySetters (C:\Users\saadaoui\Desktop\chat-app\server\node_modules\mongoose\lib\schematype.js:1220:12)
      at SchemaType.castForQuery (C:\Users\saadaoui\Desktop\chat-app\server\node_modules\mongoose\lib\schematype.js:1632:15)
      at ObjectId.handleSingle (C:\Users\saadaoui\Desktop\chat-app\server\node_modules\mongoose\lib\schematype.js:1562:15) 
      at SchemaType.castForQuery (C:\Users\saadaoui\Desktop\chat-app\server\node_modules\mongoose\lib\schematype.js:1629:20)
      at cast (C:\Users\saadaoui\Desktop\chat-app\server\node_modules\mongoose\lib\cast.js:334:39)
      at Query.cast (C:\Users\saadaoui\Desktop\chat-app\server\node_modules\mongoose\lib\query.js:4911:12)
      at Query._castConditions (C:\Users\saadaoui\Desktop\chat-app\server\node_modules\mongoose\lib\query.js:2232:10),     
  valueType: 'string',
  model: Model { User }
}

مع العلم الكود يعمل بصفة عادية.

شكرا لكم.