Access to file via lan problem

I am buy 4Tb version about a month and a half.

After a few day some files and folders reading lead my mac and win computers to read errors. But after rebooting of devise all back to normal for a next few days.

And now rebooting stop to help at all.

Other protocol(ftp and afp) and ssh work just fine.

Firmware 2.2.91

Any ideas how to fix this problem?

Can you stae the exact errors you are getting?