ESP32 WiFi "roaming" doesn't work

[tim_wiese]

I've developed an ESP32 application which is used on a mobile ESP node. So a kind of WiFi roaming is required. Means triggered by a timer, the ESP32 should check, if it's still connected to the AP with the highes RSSI in a cedrtain area. Of course all available AP's are stored in form of their credentials as SSID and PW.
Connecting to a certain AP works w/o problems, but disconnecting and reconnecting doesn't work, as i don't get any events after restarting the network.
The same goes after having done the WiFi scan, the ESP is not reconnecting after that.