linebot放上heroku无回应问题

把linebot主程式推上heroku后，发现linebot无回应
查 heroku log 发现写了下方内容

2020-08-07T09:07:34.229120+00:00 app[web.1]: 10.63.109.106 - - [07/Aug/2020 09:07:34] "POST /callback HTTP/1.1" 404 -

2020-08-07T09:07:34.230573+00:00 heroku[router]: at=info method=POST path="/callback" host=oictmainlinebot.herokuapp.com request_id=7f1a072e-ad32-4041-b5b7-32ef574de0b0 fwd="147.92.149.170" dyno=web.1 connect=0ms service=2ms status=404 bytes=394 protocol=https

这两行我看不太懂，还请大家能替我解惑，非常感谢!