Error starting scrcpy

[Egabrag]

App worked fine when first installed.

adb devices command detects both (1) USB connected phone AND (2) Wireless connected device

However, device isn't showing the mirror window. Its erratic. Earlier it worked fabulously. Now it isn't :(

Pre-requirements

Can use the scrcpy adb command globally

Required information

1. Mobile phone information : OnePlus 7T (not rooted)
2. System information
3. scrcpy version :
4. Is it possible to open the device on the command line using scrcpy? Yes - sometimes.
5. Error message