@Dustyhub 

Is your WiFi extender set up correctly and actually getting internet from your router? Does your phone has internet access when connected to this WiFi? If your phone can’t get online either, then the problem should be with the extender.

If only the camera can’t get online when connected to the extender, please check if there are any special settings on the extender. You might also want to contact the extender’s manufacturer support for help.

Since we know your camera works when connected directly to your router, the camera itself is fine. If you ask me, i would say the quickest solution in this case would be to try a different range extender.