I've done the first one (delete all wifi settings = no change) and the second one doesn't World. i push the Button for 30seconds even more and nothing happen. Today, I already done a Factory reset of the controller. Nothing change in terms of wifi. Is this possible that this issue IS due to the drone firmware version?The camera and the gimbal are built as one unit, but they are two separate components, with different control systems. It is very common to have problems with one but not the other.
The most likely resolution will be in two stages. One is to go into WIFI settings and "forget" everything that has ever been connected. A lot of WIFI will show up that was never connected and therefore will not have the "forget" option. You don't have to worry about those.
The second stage would be to reset the camera using the reset button near the SD card. The document below is a draft document. It has not even been tried it to see if it works. If the button in this document does not work, use the other button. You may even need to do a factory reset of the controller, which will mean reinstalling the FlightMode APK.