Hello @Wenqing_Deng,
Thanks for getting in touch and sorry about the trouble 
I was wondering, have you tried a complete reboot of your Roon Core?
- quit Roon
- turn off your Core
- unplug the Core for a few minutes
- plug it back in
- turn on the Core
- launch Roon
Does it help?
If not, could you please use this post as a guide to share details about your setup?