WordPress: 413 Request Entity Too Large – Plesk

I have a WP site managed on an Ubuntu server with Plesk.
For a few hours I can not upload files above 2MB.
I have made several attempts like:

• Change the settings from php.ini (verifying via phpinfo () that they were set correctly).
  Both through Plesk and manually;
• Change different PHP versions (from 5.6, 7.0.x, 7.1.x, to 7.2.x);
• Disabled firewall;
• Tested with different types and name files;
• Set the upload limit with nginx (either manually or via plesk);
• Tried to set the limit via .htaccess and / or wp-config;
• Updated WP, ​​plugins and themes;
• Disabled all plugins;
• Try to decrease the upload limit to 1 MB (in this case it displayed the limit and did not allow me to proceed with the upload);
• Tested by other PC / browsers.

On other sites uploaded to the same server, with the same settings (one is the backup of the site in question) instead I can correctly upload the files.

On the file upload screen I see the upload limit correctly (for example 64M) but if I upload a file greater than 2MB I see the error:

413 Request Entity Too Large

What could it be? Do you have any ideas / suggestions on this?

Thanks a lot!