@kenna178015 Hello, 

How about Led status when it stuck on the last step, it is Solid Green? 

If it is not Solid Green, please verify your Wi-Fi password by forgetting your Wi-Fi network on cell phone first :  
Go to Settings-> WiFi on your phone, Tap (or Long press  the router's 2.4Ghz WiFi name  ->Forget / Delete the network 
Please reconnect to your router wifi and it will ask for a password, will it accept your router password?

If so, please reset the smart plug and set up again on Kasa app, ( double-check the wifi password you put in )

Also turn off the firewall on router & Modem, and make sure there is not advanced settings that may affect the smart plug installation. 

If still the same issue, please reply to us with some details below, many thanks

May I know the model number of your Wi-Fi router and your network topology:

Kasa app version:

Model of cell phone & Android or IOS version of your phone: