JupyterHub starts, and when a user logs in, it fails to spawn a notebook server on the page

JupyterHub starts, and when a user logs in, it fails to spawn a notebook server on the page, and I check the container is started and can be exec in it , but the page show

503 : Service Unavailable
Your server appears to be down. Try restarting it [from the hub](http://127.0.0.1:16667/hub/home)

the error logs below:

01:52:33.185 [ConfigProxy] error: 503 GET /user/qycai/oauth_callback connect ECONNREFUSED 10.0.19.171:8888
[I 2021-12-10 01:52:33.189 JupyterHub log:189] 200 GET /hub/error/503?url=%2Fuser%2Fqycai%2Foauth_callback%3Fcode%3D3cL8Gq5d9kqkoZEEkYzkMHlehq9nMM%26state%3DeyJ1dWlkIjogIjM1NDE2YjExYzNmYjQ3ZTRiYzRiZDg1OTEzZDJkYjg5IiwgIm5leHRfdXJsIjogIi91c2VyL3F5Y2FpL2xhYj8iLCAiY29va2llX25hbWUiOiAianVweXRlcmh1Yi11c2VyLXF5Y2FpLW9hdXRoLXN0YXRlLW55VHd4ZG5hIn0 (@10.0.19.86) 3.21ms