Please check in your setup

Use Middleware in routes:

// routes/tenant.php
Route::middleware([
    'web',
    InitializeTenancyByDomain::class,
    PreventAccessFromCentralDomains::class,
])->group(function () {
    // Your routes here
});

Fix for AppServiceProvider:

public function boot()
{
    if (tenancy()->initialized) {
        $tenant = tenant();
        // you can access tenant('id')
    }
}

If still not working then clear the config and cache:

php artisan config:clear
php artisan cache:clear