Thank you!!! I’ve been trying to fix this for 2 days. I was REALLY tired of hearing the hubby complain, LOL! We had things go wonky a couple of weeks ago, but somehow seemed to fix themselves. This time it was clear what was happening, just couldn’t figure out how to fix it. Your solution took literally 2 minutes! Thank you again!
Thanks too - I was afraid to delete the SmartApp using the IDE but having tried all the instructions on the official support website involving resetting the hubs and my rooter to no avail I found this. Simple and didn’t involve deleting any of my smart apps.
I lost the connection after installing a Harmony hub to control some of my media gear and interact with Smartthings and Amazon Echo.
So its fine to select the hub in the ide and delete using the button, Once the Philips hub is rediscovered you’ll need to reconnect and press the button on it. After that allmy 19 bulbs were discovered and work in the apps as expected.
You da man! I’ve been struggling with this for awhile, and this does the trick. Just tell me where to send the case of beer.
Glad it worked! Nothing worse than having to start from scratch again 
This works! I too had been messing with one of my harmony hubs/alexa integration (which btw I still can’t get working, but that’s another story) and then starting last night I noticed my hue lights weren’t responding properly to motion. Deleted/Re-added it from the device list like suggested above and now it’s working. Thanks man! 
I had the same problem and i solve it. ST hub when the first connect to hue hub it save its ip address , once your hue hub shows OFFLINE in your ST app, most likely its ip address has changed. the only way to bring it up again is to give the same ip which has registered in the ST hub. you can find th ip from the app or the web as shown in the attachment
