When I turn on the vacuum cleaner, it automatically starts searching for the charging dock, even if it is positioned correctly at the dock already. Even after a (hard) factory reset, the vacuum cleaner still wants to search for the charging dock.

If the battery is (almost) empty, it will just give a message "the battery is empty, will turn off soon" but if the battery is full, it will start riding all over the place. I have no idea what it is doing. After some time, it will return to the dock, but it won't ride against the dock. It will stand approximately 20 cm away from the charging dock.

So, I have tried to do a factory reset. I can no longer connect to the vacuum cleaner from my phone. My phone says the vacuum cleaner is off-line. When turn on the vacuum cleaner, it will say "Turning on", followed by something like "Returning to charging dock" and it will either go around the house or turn itself off.

How will I enable myself to enter the setup again and re-install the vacuum cleaner?

Please note that I have tried a factory reset already. It doesn't change anything.