Grandstream Networks GWN76 Series User Manual page 58

In order to verify, you may access the bridged AP configuration, then under Status, the option "Client Bridge Mode" would be
set to Isolated like shown on the figure down below:
Important notes
The access point that will be operating on bridge mode, must be set with a fixed IP address before activating the bridge mode
on the access point.
Users must enable client bridge support option under SSID or SSID Wi-Fi settings in order to have it fully functional.
The Client Bridge requires the SSID to not have any VLAN ID enabled
USING GWN76xx AS SLAVE ACCESS POINT
Slave Mode allows the users to access to specific service and system settings.
Client Bridge
Client Bridge Mode