我跟着老师走到下载 server 的时候，我复制了.env, 也用 yarn install 过了，但是后端服务器跑不起来，似乎是有关 mongoose 的版本问题，报错如下：
老师能看下这个该怎么解决么？
yarn run v1.22.10
warning ../../../../package.json: No license field
$ nodemon --ignore 'src/tests/.ts' --exec ts-node --files src/index.ts
[nodemon] 1.19.4
[nodemon] to restart at any time, enter rs
[nodemon] watching dir(s): *.
[nodemon] watching extensions: ts,json
[nodemon] starting ts-node --files src/index.ts
(node:70120) Warning: Accessing non-existent property 'count' of module exports inside circular dependency
(Use node --trace-warnings ... to show where the warning was created)
(node:70120) Warning: Accessing non-existent property 'findOne' of module exports inside circular dependency
(node:70120) Warning: Accessing non-existent property 'remove' of module exports inside circular dependency
(node:70120) Warning: Accessing non-existent property 'updateOne' of module exports inside circular dependency
(node:70120) DeprecationWarning: Mongoose: the isAsync option for custom validators is deprecated. Make your async validators return a promise instead: https://mongoosejs.com/docs/validation.html#async-custom-validators

/qiuzhi99/server/node_modules/mongodb/lib/core/sdam/topology.js:878
new MongoTimeoutError(
^
MongoTimeoutError: Server selection timed out after 30000 ms
at Timeout. (/qiuzhi99/server/node_modules/mongodb/lib/core/sdam/topology.js:878:9)
at listOnTimeout (node:internal/timers:556:17)
at processTimers (node:internal/timers:499:7)
[nodemon] app crashed - waiting for file changes before starting...