@ADRStudio - is this down again?  Deleted and readied mine and still not working - I can control all lights and switches in the app.  It's just the smart action that is not working.

action is - switch on/off controls group on/off

@SCardamon Yes, is down again. I don't know why is down today.

@ADRStudio I'm also experiencing this issue.  I had 3 smart actions, control with a switch, where the switches also controlled multiple lamps/plugs.  Worked fine until 2-3 days ago. I deleted SmartAction and recreated by no luck. I even deleted tp-link kasa app and redownloaded, but still not working.  Is there any change this is due to a iOS upgrade?  Or is this something on TP-link side that will be fixed?

@TdocTdog  Looks like is back, at least mine is working fine now.

As was on the ThanksGiving day I almost sure the problem was on their side, the suppor  said at that time that there was a problem with Amazon Cloud that I think they use as a server, in fact the news reported problem with Amazon that day.

I didn't bother to delete or reinstalled the app this time, I just created a schedule to turn off (my case) and just waited to come back. 

Did you ever tried  SmarThings app. It has a similar feature and works fine. I have but don't use it because I want to use only one app, and Kasa it's better.