Bad server response after upgrading from 5.9.4 to 6.0.10

[Ilya]

Hello,

after upgrading from 5.9.4 to 6.0.10 I get an error

Espo.ERROR: Uncaught Exception Error: "Class 'Slim\Factory\AppFactory' not found" at C:\Users\79523\Desktop\CRM\WCRM\application\Espo\Core\ApplicationRunners\Api.php line 80 {"exception":"[object] (Error(code: 0): Class 'Slim\\Factory\\AppFactory' not found at C:\\Users\\79523\\Desktop\\CRM\\WCRM\\application\\Espo\\Core\\ApplicationRunners\\Api.php:80)"} []

What could be the reason?
php7.3, the composer file was taken from the last commit