Have you used the TTA Pie Gapp Installer? Share your experience in the comments below (or on your favorite Android forum).
This happens when the wizard permissions are not set correctly. Boot back into recovery, open the built-in File Manager, navigate to /system/priv-app/SetupWizard , and ensure its permissions are set to 0755 (rwxr-xr-x). tta pie gapp installer for android 9
Flashing system files can permanently brick your device if done incorrectly. Before moving forward, check off every item on this preparation list: Have you used the TTA Pie Gapp Installer