Not positive I totally follow, but it sounds like you are using a virtual switch to trigger your lights?
I would start over… create a new virtual on off switch(see link below), and tie that virtual switch to your living room lights via Smart lighting. Then authorized that virtual switch to use IFTTT from the SmartApp in ST. Then recreate your IFTTT applet and see what happens, Make sure you watch your activity feeds as you trigger for ideas of where it might be broken.
I believe what is happening, because I see it too, is if you go back in and edit your IFTTT applet the SmartThings device is blank.
I can confirm, at least on my side is that if you select the device and save the applet it will indeed save and operate correctly. But, if you go in to edit it again you will again have to reselect the SmartThings device.
Thanks, you’re on to something here. My applet (based on email received in my Gmail account) was failing every time and I thought the missing device was the reason.
I have now set up a test applet which is triggered by time. Going back into the app, the Smartthings device is also missing, but the applet triggers the Smartthings device despite of that.
The problem seems to be with the Gmail service in IFTTT. No matter how I set it up, the will not trigger any Smartthings device. If fails without an error description. The applet fires when the trigger email is received but fails to switch the Smartthings device.
I have now tried the Gmail service with other services as well, and none works. I disconnected and reconnected by Gmail account to IFTTT, but still no luck.
The issue therefore appears to by the Gmail service in IFTTT.