@Tera12 Followed the instructions and rebooted dimmer and all is well! https://community.tp-link.com/us/smart-home/forum/topic/589080?replyId=1150696

Started recently. HS220 dimmer has worked fine with Alexa. Now displays Device Unresponsive or Server unresponsive. Have tried several times adding / removing device from Alexa and Kasa apps.