Why doesn't ajaxform+formit send emails with some file types?

Question

MODX

Hello
Standard mail form on ajaxform+formit
It seems that everything worked and there was no sadness, until I accidentally checked the possibility of sending a zipped file - it didn’t come.
A strange pattern was established by the poke method
Image files, pdfs, text files, documents (doc, txt ..) - everything is fine, letters are sent and received. Some miracles are happening with archives, at first I thought that only zip, but rar and 7z
are the same (maybe something else) - letters do not arrive in 90%
10)

The validator was only at the maximum size - turned it off for everyone,
Ajaxform does not help, does not give any errors, writes that the letter was successfully sent in all cases

Where to dig?