Site Sensor - disarming itself?

Has anyone else experienced a site sensor disarming itself? I have set up a site sensor to read tomorrow’s temperatures and weather (open weather). It seems to disarm itself after a while. Can anyone make some suggestions as to why and what I might look at to stop it disarming?

Thanks.

Check your house modes setup under My Modes on the Vera UI dashboard

Thanks once again for a prompt response. I recon that was it. Solved!