@Squintyeyed Pug, as it turns out, you may have been right. There is a website: http://www.tplinkcloud.com where you can setup an account and TP-Link support people suggested I try there....

Squintyeyed Pug wrote You are doing this from your iPhone? Can you try making a TP-Link account at the website? Then you should be able to just log in on the app. Apparently I've messed up my Kasa...