The problem resolved !
I think the latest version of Word Press doesn’t support the XML files!
I used 7zip and I compressed the XML to tar and I tried to import the tar file and it works fine.
So I think the problem is the latest version of Word Press or the Hosting provider blocking the XMLs files for security reasons.
Anyhow I resolved the problem and thank you very much for your assistance and your support.
Have a good day and Happy Holidays
I erase the multisite version and I install the default version of WP and I tried to Import XML data and again the same problem. 🙁
Any idea how to resolve the problem ?