file transfer not working v.15.4.8332

AnZo

Good afternoon. A bunch of PCs (v.15.4.8332) - Android tablets Samsung (QS v.15.4.61) Everything is connected, it works, it is controlled, except for one but the file transfer has disappeared. I found the PC version 15.3.8497 as a method of selection - with it, file transfer works as before. What is the problem, who came across, tell me! One tablet with a root, the other without (no effect), put on the Host tablet - there is no file transfer either. Did the developers cut this feature? A bunch of PC - PC - file transfer is!
Thanks for the help!