OTA not working

I’m using 2 pieces of BLE gateway v4.
GateWayConfigTool version is 1.2.6
BLE gateway FW version is, HW version is 4.0
When I click “Adavanced - Update”
MSG shows “Firmware is updated successful!”
But Dashboard shows FW
After several reset, its same.

Strange thing is, it’s only one gateway’s problem.
One udpated successfully, but the other one is not.

What’s wrong?

We’ve just pushed OTA files for v1.2.5.20. Please try to update again.

It becomes
Now… I can choose message format to JSON type.
Thank you again.