Php Artisan package:discover –ansi handling the post-autoload-dump event returned with error code 255

Hey there, I try to deploy the laraship app to Mamp-pro. Everything goes smoothly until I got this error. "Generating optimized autoload files ocramius/package-versions: Generating version class... ocramius/package-versions: ...done generating version class > Illuminate\Foundation\ComposerScripts::postAutoloadDump > @php artisan package:discover --ansi Script @php artisan package:discover --ansi handling the post-autoload-dump event returned with error code 255" so from this error when I run the command of  "php artisan key:generate" artisan didn't generate a key for .env file. artisan didn't migrate too. I stuck Any suggestion? MacX - Catalina Mamp-Pro | php 7.4.2