Unable to activate TTN Gateway

Unable to activate a new TTN Gateway
When attempting Gateway Activation Configure (Step 3)
(a successfully registered gateway (Things-Gateway-001EC03B3B8E )
After Reset (power cycle while holding pink button)
with Ethernet disconnected, LED1 solid ON, LED2 flashing, LED3-5 OFF.
Using Chrome on Win10 Pro
(same results with Firefox ESR 52.7.2 (64-bit) and Microsoft Edge 41.16299.248.0)
After filling in WiFi SID, Security Mode: WPA 2 Personal & Password
and pressing “Configure Gateway” Button
Immediately received following message:
Request has been terminated.
Possible causes the
Network is offline, Origin is not allowed by Access-Control-Allow-Origin, the page
Subsequent Button presses give cause the same error message.
Updated to The Things Gateway Firmware from 3/15 version via SD card
(from https://github.com/TheThingsProducts/gateway/tree/master/firmware )
yielded same results.
Attempted with Ethernet activation. Also, same results.

A post was merged into an existing topic: TTN GATEWAY central 2