@Michel1961 

Good day.

Thank you very much for your time and patience.

For your case, please check the following information:

1. After the setup, did the top wireless signal light lit up as green?
2. What is the model number of your Ziggo Router?
3. Did the extender work fine before?

Have you tried to reset it  by holding the reset button for 10s and set it up again: https://www.tp-link.com/support/download/tl-wa860re/v1/#video

(please also double check the Wi-Fi password and make sure there is no mistakes)

Thank you~