I get the error when trying to get to the site: 

Whoops, looks like something went wrong.

and this in error_log: [13-Sep-2018 21:18:23 UTC] PHP Fatal error:  Class 'Modules\Downloads\Providers\DownloadsServiceProvider' not found in /vendor/laravel/framework/src/Illuminate/Foundation/Application.php on line 612

I tried to create a new Module but i've already delete it when i got the error but the error continues.

Hi Vitor,

Maybe this page will helped your module; https://akaunting.com/docs/developer-manual/modules

If we come to your error, please go to framework/cache/ and data please firstly delete data folder and after delete your module in module folder and refresh page.

Have a nice day!

It worked, thanks. It was just the cache.