Unable to import XML file

Hello, I’m creating a new site for the client and am trying to import content from one of his existing site to use as a base. The file exports correctly but when running WordPress Importer, I get the following error:

Import WordPress
Sorry, there has been an error.
File is empty. Please upload something more substantial. This error could also be caused by uploads being disabled in your php.ini or by post_max_size being defined as smaller than upload_max_filesize in php.ini.

File is 9.87 mb. I’ve increased post_max_size to 32 mb but still getting the same error.

The site is https://thailand-car-dealer.org/