Unable to prepare route [api/admin/logout] for serialization. Another route has already been assigned name [logout].

This error indicates that there is a conflict in your routing configuration where two routes are assigned the same name (logout). To resolve this, you’ll need to ensure each route has a unique name. Here are some steps you can follow to troubleshoot and fix this issue:

1.Check your route definitions: Look through your route files (typically in routes/web.php, routes/api.php, or similar) and find all instances of routes named logout.

2.Rename one of the conflicting routes: Ensure that each route has a unique name. For example:

// routes/web.php
Route::get('logout', 'Auth\LoginController@logout')->name('logout.web');

// routes/api.php
Route::post('admin/logout', 'Admin\Auth\LoginController@logout')->name('logout.api');

3.Clear your route cache: Sometimes, cached routes can cause issues. Run the following commands to clear and re-cache your routes:

php artisan route:clear
php artisan route:cache

4.Check your middleware and service providers: If you’re using route middleware or defining routes in service providers, ensure there are no conflicting route names there as well.

5.Search your project for duplicate route names: Perform a search in your project directory for name('logout') to quickly find and resolve any duplicate route names.