Make sure that,
On your real mobile, you have "allowed remote computer to connect".
"Your laptop's IP address" is configured as a proxy on your mobile manually.
Your mobile's proxy port number is configured 8866 manually.
Try pinging your phone IP address from your computer.
If it is still not working maybe try "fiddler classic" instead of "Fiddler Everywhere". Please setup your Android device to use "Fiddler" tool as a proxy. Then you can use fiddler tool for debugging on Windows. You just need to install fiddler root certificate.
Refer below link:
https://www.telerik.com/blogs/how-to-capture-android-traffic-with-fiddler
And to capture iOS Traffic with Fiddler: https://www.telerik.com/blogs/how-to-capture-ios-traffic-with-fiddler