# Windows sensor **URL:** \ **Category:** Free discussion\ **Created:** [June 10, 2024, 8:01pm UTC](https://forum.ewelink.cc/t/windows-sensor/35835 "2024-06-10T20:01:30Z")\ **Posts on this page:** 8\ **Page:** 1
**Author:** ![humberto.felipe](https://avatars.discourse-cdn.com/v4/letter/h/ec9cab/32.png) [@humberto.felipe](https://forum.ewelink.cc/u/humberto.felipe)\ **Post date:** [June 10, 2024, 8:01pm UTC](https://forum.ewelink.cc/t/windows-sensor/35835/1 "2024-06-10T20:01:30Z")
I have 4 zigbee window sensors. They worked well for at least two years. Now they are constantly offline. There was no change in distances or systems. Some presence and window sensors work without problems, others lose contact. I restart the sensor more than once and they go offline again ---
**Author:** ![jam3](https://dub1.discourse-cdn.com/flex005/user_avatar/forum.ewelink.cc/jam3/32/7918_2.png) [@jam3](https://forum.ewelink.cc/u/jam3)\ **Post date:** [June 11, 2024, 2:17am UTC](https://forum.ewelink.cc/t/windows-sensor/35835/2 "2024-06-11T02:17:47Z")
Have you replaced the batteries in these 2 years? ---
**Author:** ![humberto.felipe](https://avatars.discourse-cdn.com/v4/letter/h/ec9cab/32.png) [@humberto.felipe](https://forum.ewelink.cc/u/humberto.felipe)\ **Post date:** [June 11, 2024, 11:19am UTC](https://forum.ewelink.cc/t/windows-sensor/35835/3 "2024-06-11T11:19:20Z")
Yes, I changed it, the batteries are full ---
**Author:** ![jam3](https://dub1.discourse-cdn.com/flex005/user_avatar/forum.ewelink.cc/jam3/32/7918_2.png) [@jam3](https://forum.ewelink.cc/u/jam3)\ **Post date:** [June 11, 2024, 1:44pm UTC](https://forum.ewelink.cc/t/windows-sensor/35835/4 "2024-06-11T13:44:34Z")
What are these sensors connected to? Perhaps something has changed in the environment, in terms of the radio signal. Any new devices using WiFi, for example? Do you live in a building or is it a house? ---
**Author:** ![ward](https://dub1.discourse-cdn.com/flex005/user_avatar/forum.ewelink.cc/ward/32/10437_2.png) [@ward](https://forum.ewelink.cc/u/ward)\ **Post date:** [June 12, 2024, 2:11am UTC](https://forum.ewelink.cc/t/windows-sensor/35835/5 "2024-06-12T02:11:52Z")
> [@humberto.felipe](#): > > Now they are constantly offline. Looks like a network inference issue, the hub/AP decides to use a new channel and they don’t get along well with each other. It would be good to think about what’s changed before the issue occurred like firmware updates, new ap, or changed positions of certain devices. ---
**Author:** ![humberto.felipe](https://avatars.discourse-cdn.com/v4/letter/h/ec9cab/32.png) [@humberto.felipe](https://forum.ewelink.cc/u/humberto.felipe)\ **Post date:** [June 12, 2024, 12:18pm UTC](https://forum.ewelink.cc/t/windows-sensor/35835/6 "2024-06-12T12:18:10Z")
thanks, I will see this ---
**Author:** ![mario.bianchi](https://avatars.discourse-cdn.com/v4/letter/m/f17d59/32.png) [@mario.bianchi](https://forum.ewelink.cc/u/mario.bianchi)\ **Post date:** [July 18, 2024, 10:55pm UTC](https://forum.ewelink.cc/t/windows-sensor/35835/7 "2024-07-18T22:55:24Z")
Couple of things I saw with those sensors. They use WiFi protocol B, so check if your wifi network has protocol B enabled. In some routers it comes off by default. It could be off as a result of a router firmware upgrade. The other thing could be that some wifi netowork tend to remove sessions that ended and as the sensor send information just ocassionally may be the router is killing those wifi connections. See if you have a setting that could be affecting them and raise the time out so those sporadic wifi connections are mantained open. Hope this helps. ---
**Author:** ![jmacch](https://avatars.discourse-cdn.com/v4/letter/j/838e76/32.png) [@jmacch](https://forum.ewelink.cc/u/jmacch)\ **Post date:** [July 18, 2024, 11:38pm UTC](https://forum.ewelink.cc/t/windows-sensor/35835/8 "2024-07-18T23:38:58Z")
I have 8 sensors in my home and also there are a couple constantly off-line. I have to reset them to return them to on-line. For me there is an issue with these sensors.