What is 997 error at the client?

USB Edgeport
1

INFO :Connection 703 closed, (rx) error 997

And device log:
Jul 23 22:01:51 AW08-002068 awusbd[2137]: 10.xx.xx.xx connected as connection 13 (secure)
Jul 23 22:02:12 AW08-002068 awusbd[2137]: Connection 13 keepalive timeout (21) 3/20