Hey@pdb1976 , 

May I know did you try this troubleshoots guide RE installation step by step, kindly give it a try and let us know if it works for you:
Has connected to TP-Link extender but no internet, what can I do?
https://community.tp-link.com/en/home/forum/topic/198516

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 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?

May I know how about the Led status on range extender after installation, , thank you.