Hello   @Jeyxdee 

If you use RE in Access point mode (wired to router ) but can not connect to Wiif of the RE， please also try some tips here 

1. Please connect a computer---router by cable, confirm router can provide the Internet by a wired connection
2. Try a different LAN port on the router 
3. Try a different cable between Access Point and router 
4. Reset Access point and reboot the main router 
Reset: with the access point powered on, use a pin to press and hold the Reset button until the Power LED starts blinking, then release the button.