antminer d3 Hardware Version Socket connect failed: Connection refused

[xgdx]

hi i have many D3 and on most of them every few hours problem: Hardware Version Socket connect failed: Connection refused or some chains disappears.
In first case, when I update pool to another and rollback to the first one, problem disappear for next few hours. Anybody has solution for that? That's not pool problem because I have lot of D3 and have configured different pools for them.. I'va updated soft to newest.