Wifi connection lost after approximately 1 hour


After approximately one hour of stable operation, the connection with wifi is lost and cannot be restored.

Raspberry 2B+
USB Wifi dongle: Realtek Semiconductor Corp. RTL8191SU 802.11n WLAN Adapter
USB connection to NAD 3020D

Volumio version 3.251 using Spotify connect plugin

Logs: http://logs.volumio.org/volumio/aUaw5Sm.html

Wifi dongle is connected to Raspberry USB port, but I’ve also tried a powered USB hub resulting in the same problem.