crontab 运行 flask 的一个 app 总是执行不成功

crontab 运行一个检测脚本就是 app 挂了执行：nohup /usr/bin/python3 /app/app.py > /log/app.log & 执行完成后进程是起来了的，但是访问接口报 500 错误， 查看输出日志之后发现：

 * Serving Flask app "app" (lazy loading)
 * Environment: production
   WARNING: This is a development server. Do not use it in a production deployment.
   Use a production WSGI server instead.
 * Debug mode: off

相比正常执行少了最后那一行

 * Serving Flask app "app" (lazy loading)
 * Environment: production
   WARNING: This is a development server. Do not use it in a production deployment.
   Use a production WSGI server instead.
 * Debug mode: off
 * Running on http://0.0.0.0:5200/ (Press CTRL+C to quit)

各位大佬能凭丰富的经验定位出是哪里问题吗