Unable to receive files with extension ".7z"

Hello,

If a ticket is opened for me, which includes an appendix with the extension .7z, it will not transfer.

I have also added in the admin area, the ending ".7z" under the accepted file types, but they just will not matter.

the upload folder on the server it is not.

what could it be, perhaps, the ending is just too short?

Note:

I used Google to translate, so do not be surprised if the English should not be so good.

Thanks in advance