Yeelight thing state unknown

Hi
My Yeelight led strip binding change his state from online to offline and then to unknown almost everyday
Why this is happened?
When I try to control it from Openhab I need to send command at least 2 time to restore thing state to online again
Why this is happened?
Can I keep it online?

Oded

2019-07-19 16:45:57.573 [hingStatusInfoChangedEvent] - 'yeelight:stripe:1' changed from UNKNOWN to OFFLINE: Device is offline!

2019-07-19 16:45:57.596 [hingStatusInfoChangedEvent] - 'yeelight:stripe:1' changed from OFFLINE: Device is offline! to UNKNOWN

2019-07-19 16:45:57.573 [hingStatusInfoChangedEvent] - 'yeelight:stripe:1' changed from UNKNOWN to OFFLINE: Device is offline!

2019-07-19 16:45:57.596 [hingStatusInfoChangedEvent] - 'yeelight:stripe:1' changed from OFFLINE: Device is offline! to UNKNOWN

2019-07-19 16:45:58.065 [hingStatusInfoChangedEvent] - 'yeelight:stripe:1' changed from UNKNOWN to ONLINE

2019-07-19 17:23:52.578 [hingStatusInfoChangedEvent] - 'yeelight:stripe:1' changed from OFFLINE: Device is offline! to UNKNOWN

2019-07-19 17:23:55.648 [hingStatusInfoChangedEvent] - 'yeelight:stripe:1' changed from UNKNOWN to ONLINE

2019-07-19 21:36:20.320 [hingStatusInfoChangedEvent] - 'yeelight:stripe:1' changed from OFFLINE: Device is offline! to UNKNOWN

2019-07-20 09:52:14.654 [ome.event.ItemCommandEvent] - Item 'YeelightLedSwitchStartCf' received command ON

2019-07-20 09:52:14.684 [vent.ItemStateChangedEvent] - YeelightLedSwitchStartCf changed from OFF to ON

2019-07-20 09:52:14.716 [ome.event.ItemCommandEvent] - Item 'YeelightLEDCommand' received command set_power;"on","smooth","2000,4"

2019-07-20 09:52:14.720 [nt.ItemStatePredictedEvent] - YeelightLEDCommand predicted to become 

2019-07-20 09:52:14.780 [hingStatusInfoChangedEvent] - 'yeelight:stripe:1' changed from UNKNOWN to OFFLINE: Device is offline!

2019-07-20 09:52:14.793 [vent.ItemStateChangedEvent] - YeelightLedSwitchStartCf changed from ON to OFF

2019-07-20 09:52:14.796 [ome.event.ItemCommandEvent] - Item 'YeelightLEDCommand' received command set_power;"on","smooth","2000,4"

2019-07-20 09:52:14.801 [nt.ItemStatePredictedEvent] - YeelightLEDCommand predicted to become 

2019-07-20 09:52:14.812 [vent.ItemStateChangedEvent] - YeelightPowerState changed from UNKNOWN to OFFLINE

2019-07-20 09:52:18.866 [hingStatusInfoChangedEvent] - 'yeelight:stripe:1' changed from OFFLINE: Device is offline! to UNKNOWN

2019-07-20 09:52:18.906 [vent.ItemStateChangedEvent] - YeelightPowerState changed from OFFLINE to UNKNOWN

2019-07-20 09:52:21.110 [hingStatusInfoChangedEvent] - 'yeelight:stripe:1' changed from UNKNOWN to ONLINE

==> /var/log/openhab2/openhab.log <==

2019-07-20 09:52:21.114 [INFO ] [light.internal.lib.device.DeviceBase] - status = DeviceStatus [isPowerOff=true, r=255, g=80, b=22, color=16732182, brightness=38, ct=3200, hue=15, sat=91, isFlowing=true, delayOff=-1, mFlowItems=[ColorFlowItem [duration=4000, mode=1, value=16776960, brightness=38], ColorFlowItem [duration=4000, mode=1, value=65280, brightness=38], ColorFlowItem [duration=4000, mode=1, value=16744192, brightness=38], ColorFlowItem [duration=4000, mode=1, value=255, brightness=38]], mode=MODE_COLOR, isMusicOn=false, name=]

==> /var/log/openhab2/events.log <==

2019-07-20 09:52:21.160 [vent.ItemStateChangedEvent] - YeelightPowerState changed from UNKNOWN to ONLINE