connecting external AP (TP-LINK) to RB951u hotspot on Ether4

Hi

I just bought a new RB951ui for the purpose of extending my network by wifi using a TP-Link access point (12 Dbi) as radio and TP-LINK omni direction antenna (15DBi).

After all configuration was confirmed ok, with TP-Link Radio set to AP Mode, and POE connected to Ether4; while RB linked to the Router/Gateway at Ether1, The Hotspot was configured for Ether4 and transmission was ok. Meaning while connected to the AP over wifi, I could ping the router and other devices connected to it. but while trying to connect to internet, the hotspot login page did not show.

What could be the problem, please, I really need assistance.

Thanks.