Sequelize inserts a Datagram error after establishing a many-to-many association - Codes Helper

background:

const EventUser = sequelize.define("userEvents", {
    payStatus: Sequelize.STRING
})
User.belongsToMany(Event, { through: EventUser})
Event.belongsToMany(User, { through: EventUser})

use:

        const event = await EventModel.getEventDetail(eventId);
        const user = await UserModel.findUserById(userId);
        //eventuser
        try {
            await event.addUser(user, { through: { payStatus: payStatus }}) //
        } catch (e) {
            console.log(e)
        }

error log is as follows:

Error: Invalid value user {
  dataValues:
   { id: 1,
     nickname: null,
     session_key: "test",
     phone: null,
     email: null,
     money: null,
     city: null,
     avatarUrl: null,
     sex: null,
     birthday: null,
     lastLoginTime: 2019-01-25T06:26:27.000Z,
     registerTime: 2019-01-25T06:26:27.000Z,
     openId: "test",
     createdAt: 2019-01-25T06:26:27.000Z,
     updatedAt: 2019-01-25T06:26:27.000Z },
  _previousDataValues:
   { id: 1,
     nickname: null,
     session_key: "test",
     phone: null,
     email: null,
     money: null,
     city: null,
     avatarUrl: null,
     sex: null,
     birthday: null,
     lastLoginTime: 2019-01-25T06:26:27.000Z,
     registerTime: 2019-01-25T06:26:27.000Z,
     openId: "test",
     createdAt: 2019-01-25T06:26:27.000Z,
     updatedAt: 2019-01-25T06:26:27.000Z },
  _changed: {},
  _modelOptions:
   { timestamps: true,
     validate: {},
     freezeTableName: true,
     underscored: false,
     underscoredAll: false,
     paranoid: false,
     rejectOnEmpty: false,
     whereCollection: { id: 1 },
     schema: null,
     schemaDelimiter: "",
     defaultScope: {},
     scopes: [],
     indexes: [],
     name: { plural: "users", singular: "user" },
     omitNull: false,
     sequelize:
      Sequelize {
        options: [Object],
        config: [Object],
        dialect: [Object],
        queryInterface: [Object],
        models: [Object],
        modelManager: [Object],
        connectionManager: [Object],
        importCache: [Object],
        test: [Object] },
     hooks: {},
     uniqueKeys: { user_openId_unique: [Object] } },
  _options:
   { isNewRecord: false,
     _schema: null,
     _schemaDelimiter: "",
     raw: true,
     attributes:
      [ "id",
        "nickname",
        "session_key",
        "phone",
        "email",
        "money",
        "city",
        "avatarUrl",
        "sex",
        "birthday",
        "lastLoginTime",
        "registerTime",
        "openId",
        "createdAt",
        "updatedAt" ] },
  __eagerlyLoadedAssociations: [],
  isNewRecord: false }
    at Object.escape (D:\project\koa2-community\node_modules\sequelize\lib\sql-string.js:66:11)
    at Object.escape (D:\project\koa2-community\node_modules\sequelize\lib\dialects\abstract\query-generator.js:934:22)
    at _joinKeyValue.value.map.item (D:\project\koa2-community\node_modules\sequelize\lib\dialects\abstract\query-generator.js:2369:69)
    at Array.map (<anonymous>)
    at Object._whereParseSingleValueObject (D:\project\koa2-community\node_modules\sequelize\lib\dialects\abstract\query-generator.js:2369:52)
    at Object.whereItemQuery (D:\project\koa2-community\node_modules\sequelize\lib\dialects\abstract\query-generator.js:2127:19)
    at Utils.getComplexKeys.forEach.prop (D:\project\koa2-community\node_modules\sequelize\lib\dialects\abstract\query-generator.js:1994:25)
    at Array.forEach (<anonymous>)
    at Object.whereItemsQuery (D:\project\koa2-community\node_modules\sequelize\lib\dialects\abstract\query-generator.js:1992:35)
    at Object.getWhereConditions (D:\project\koa2-community\node_modules\sequelize\lib\dialects\abstract\query-generator.js:2456:19)
    at Object.selectQuery (D:\project\koa2-community\node_modules\sequelize\lib\dialects\abstract\query-generator.js:1140:28)
    at QueryInterface.select (D:\project\koa2-community\node_modules\sequelize\lib\query-interface.js:1105:27)
    at Promise.try.then.then.then (D:\project\koa2-community\node_modules\sequelize\lib\model.js:1604:34)
    at tryCatcher (D:\project\koa2-community\node_modules\bluebird\js\release\util.js:16:23)
    at Promise._settlePromiseFromHandler (D:\project\koa2-community\node_modules\bluebird\js\release\promise.js:512:31)
    at Promise._settlePromise (D:\project\koa2-community\node_modules\bluebird\js\release\promise.js:569:18)
    at Promise._settlePromise0 (D:\project\koa2-community\node_modules\bluebird\js\release\promise.js:614:10)
    at Promise._settlePromises (D:\project\koa2-community\node_modules\bluebird\js\release\promise.js:693:18)
    at Async._drainQueue (D:\project\koa2-community\node_modules\bluebird\js\release\async.js:133:16)
    at Async._drainQueues (D:\project\koa2-community\node_modules\bluebird\js\release\async.js:143:10)
    at Immediate.Async.drainQueues (D:\project\koa2-community\node_modules\bluebird\js\release\async.js:17:14)
    at runCallback (timers.js:810:20)

ask the sequelize boss to solve the problem