S7-1500 Driver Socket Connection closed

Hi ,
I am trying to connect S71500 PLC using OPC UA server, I have configure device successfully and it is showing Connected. I have configure OPC UA server which is showing Connected as well.
i congigure few tags in the designer , which are with good Quality but after some time All tags shown Bad Quality.
I have restarted gateway service , Recreated new device but that also showing same Bad Quality.
Could you please help to resolve this issue.?