Hey TP-LINK comunity!

Please help! I'm having this problem for a long time! This is my last shot! Hope someone can solve it

I'm using an TL-WA850RE as access point (updated the Firmware Version to the last version, downloaded it from https://www.tp-link.com/br/support/download/tl-wa850re/#Firmware), using an Ethernet cable from the router/wifi 1 and plugging the Ethernet cable in the Tp-link extender.

The first thing I do when start the configs is change the mode from extender mode to access point mode (Doing so, the DHCP should be disregarded or desable by default, right?).

The problem:

The extender does not recognize the internet from the Ethernet cable. If i plug the same cable in the desktop, the internet works fine.

What can i change to make this works? I've already tried everything!! For example: Changed the IP from the extender as a fixed IP, automatic IP, disabled the DHCP, enabled DHCP (this made the wifi unconnectable). I think there's some configuration I'm missing to make it works.

PS: My router/wifi1 doesn't have a WAN port, only LAN. All other equipments like mobiles/laptops/desktops connect on the wifi 1 just fine (by wifi or ethernet cable). 

PS2: Didn't tryed to set as an exterder, since the distance from the router is too far.

Thanks in advance.

301ce